Third seed Karolina Pliskova is among the favourites to win the women's singles at the US Open and will play Tunisia's Ons Jabeur in the third round on Friday.

In her latest BBC Sport column, the Czech discusses her relationship with twin sister Kristyna, who is also a WTA Tour player, how they shared a hotel room before they played each other in Birmingham recently and what she bought Kristyna for beating her…

When the draw for a Grand Slam tournament is made I'm always worried that Kristyna and I will be drawn against each other in the first round - that would be the worst day of my life!

There would be too much pressure and too many nerves because the Grand Slams are so important and mean so much to us.

So it is always a relief when my sister is in the opposite half.

That's what happened here at the US Open, although it was sad that she lost to Elise Martens in their second-round match on Thursday.

We don't watch the draw as it is being made, nor do we follow it on social media, and then when we do eventually see it we message and always say: 'Phew, we are not playing each other!'

We have only played each other once on the WTA Tour and that came a few months ago in Birmingham.

It was a very difficult situation for both of us - and the worst thing was that we were sharing a hotel room at the tournament!

We have played each other many times when we were younger - in qualifiers and on the lower-ranked tours - but we hadn't played for about six or seven years.

We had come close a couple of times in main draws but either I lost or she lost earlier, and also I had to withdraw once because of injury when we were supposed to play in Prague.

So it felt like everybody was waiting for this match to happen, the Czech media were excited and many people were talking about the match.

'Our parents couldn't watch'

It was a strange atmosphere in our hotel room on the morning of the match.

Kristyna and I were trying to be calm and act normal, but all the people around us and our teams were stressing and wanted to talk about it so much.

Thankfully our parents weren't there in Birmingham, I can't imagine how horrible it was for them. They didn't even watch on television back in the Czech Republic.

My mum doesn't usually like to watch our matches anyway because she is too nervous. My father usually does watch matches - but not this one. He did something else to take his mind away from it.

So we both felt very nervous and didn't know what would happen, if we would play good tennis or bad tennis.

It was huge pressure for me because if you look at the rankings I should win easily.

Of course I wanted to win the match, but I also didn't want my sister to lose. It was an emotional rollercoaster. We ended up playing a long match and Kristyna won 6-2 3-6 7-6 (9-7)!

It was the biggest victory of her career - she had never beaten a top-five player before that.

Kristyna is ranked 86th at the moment but I believe she has the ability to improve that a lot. She is not easy to beat.

If we could both be ranked in the top 10 together that would mean a lot to both of us - even more to her of course - and our families.

But that would also mean we would play each other even more, which is something I'm not sure I would enjoy!

Maybe it is something you could get used to if it is happening more often, and then we wouldn't be as super stressed about it like we were in Birmingham.

'Sometimes I talk to Kristyna more than my husband'

Of course we look similar because we are identical twins. However, I think we have aged a little differently, and we try to be different because we have never wanted to be the same.

We have different tattoos. She is a little more blonde. And our personalities are quite different.

But sometimes we think in the same way, and we often say the same thing at the same time - that makes people laugh.

She thinks a little more about stuff and is more responsible. She is two minutes older - so maybe she is trying to be like the boss a little bit and protect me!

We still give each other advice about tennis; we give advice to each other about everything in life.

Barely an hour goes by when we aren't talking on the phone - I text "hi" as soon as I wake up and and we continue all day on WhatsApp.

Sometimes I speak to her more than my husband! He doesn't mind though and he's happy for Kristyna to hang out when it is just the three of us.

The week before the US Open we went to watch some Broadways shows together - Pretty Woman and Frozen - and had a few dinners, and also did some walking and shopping.

With us being in different parts of the draw - I played Monday and Wednesday, and Kristyna played Tuesday - we have not done much in the past three or four days because you don't want to go into Manhattan and waste energy.

I need all my focus on going as far as I can in the tournament and hopefully winning my first Grand Slam.

Karolina Pliskova was talking to BBC Sport's Jonathan Jurejko at Flushing Meadows

American teenage sensation Coco Gauff is set for an intriguing US Open third-round match against defending champion Naomi Osaka after beating Timea Babos 6-2 4-6 6-4 on Louis Armstrong Stadium.

The 15-year-old, who came to prominence at Wimbledon, and the Hungarian world 112 produced a superb spectacle.

Gauff broke three times in the opening set before Babos fought back to level.

In a third set of lung-bursting rallies, Gauff crucially broke in the 10th game to seal victory.

The American is back on court on Friday for a doubles match and said that she would think about the match against Japanese world number one Osaka on Saturday - the day of their encounter.

She also paid tribute to Babos for her part in a thrilling match, saying: "Timea played so good and I'm so happy to get through.

"I was tested a lot. We both just tested each other. If I didn't win the last point maybe she would have won the match."

Seven years ago Will Addison was part of an England squad that swept to the Under-20 Six Nations Championship.

The former Sale Sharks back started the final-round win over Ireland as England took the title ahead of France and Ireland on points difference.

Peers such as George Ford, Elliot Daly and Kyle Sinckler have now become mainstays in Eddie Jones' squad but Addison will try to force his way into Ireland's World Cup squad with an eye-catching display against Wales on Saturday.

The versatile playmaker now has a chance to prove that England's loss has been Ireland's gain when he starts Saturday's World Cup warm-up game against Wales in Cardiff.

"Will is an incredibly classy player," enthuses his Ireland team-mate Jacob Stockdale, who has watched Addison at close quarters since his move to Ulster last summer.

"He can easily play 13, 15 and wing, he's really skilful and he's got an incredible rugby brain so he hasn't had any problems sliding in pretty seamlessly into the set-up.

"He's been class for us at Ulster so for him to come down into Ireland camp, yeah there were a few days when he was a bit nervy and I had to put the arm around him, the old experienced player! Will's been class and he's done very well."

Having made his debut as a substitute in Ireland's against Italy in November, Addison then started the subsequent autumn Tests against Argentina and USA as he was fast-tracked into the Irish set-up before injury abruptly ended his season in January.

It is testament to the regard in which Schmidt holds Addison that despite a seven month lay-off, he remains in contention for a seat on the plane to Japan.

It started with a text message out of the blue

Addison and some team-mates were on a night out in his hometown of Penrith when his phone lit up with a message from an unknown number claiming to be from Schmidt.

The Ireland head coach had been monitoring Addison's progress through the ranks at Sale after becoming aware that his mother, Caroline, grew up in County Fermanagh and that she had brought Will back to visit her family every summer.

Schmidt stayed in touch, even after Addison turned down an approach to join Munster in favour of remaining at Sharks, offering advice and pointers on how he might improve his game.

But Sale was his club and his loyalty was rewarded when he was made captain by director of rugby Steve Diamond after graduating from the Sale Jets academy.

Former England A international Pete Anglesea can still remember the day he first saw a 14-year-old Addison at a rugby camp in Barnard Castle School in Durham.

"I'd just retired from playing for the first team and I joined the academy staff and Will had been spotted at this rugby camp," Anglesea recollects.

"One of our coaches phoned me and asked me to drive up there to do some coaching. It's a couple of hours up the road but he said 'there's a lad there that I'd really like you to have a look at and see what you think' and that was Will.

"I drove up the following morning and it was sort of immediate, within 10 minutes you could see how he was very much a younger, rawer version of what he is today but you could already see the huge talent that he had."

Brave and skilful with the heart of a lion

Although he had never spoken to Addison about his Irish heritage, Anglesea is not surprised to see how quickly his former pupil has risen through the ranks at Ulster and Ireland.

The 26-year-old even trained with the Irish squad before his arrival at Ulster - arranging his holiday in Australia to coincide with Ireland's 2018 tour Down Under.

"He was one of those lads who just had that natural raw talent, he was one of those people who was good at all sports, I remember a few times seeing him play football or cricket and he just excelled," said Anglesea, who is now a first team coach at Sale.

"It was strange for me to see him playing with Ulster for the first time where he was getting hold of the ball and he's still exciting. He's one of those players who gets the crowd on their toes.

"As a rugby player, he's brave with good skills and the heart of a lion.

"I've seen him do fitness sessions where he's nearly collapsing because he puts his body under that much strain but he just never gives in."

BOD was his hero but a Welshman sold him on Belfast

Addison, who idolised Brian O'Driscoll when he was growing up in the Lake District, was always proud of his Irish roots and when a call came from his former Sale team-mate Dwayne Peel two seasons ago, he knew he had to make a decision on his future.

Peel, who is the Ulster attack coach, floated the idea of moving to Belfast and forcing his way into the Ireland set-up in time for the World Cup.

It was a winning sales pitch by the ex-Wales international.

"When his name came up, Dwayne spoke very highly about Will, his attributes and how he would fit well with the style of rugby the coaches were looking to implement," recalls Ulster operations director Bryn Cunningham.

"We had the luxury of Jared Payne playing at 13 at Ulster for a long period, he was probably one of the best Ulster players of the modern era, and Will has a lot of similar traits in the way that he runs, the lines that he picks, the body swerve he's got and that little injection of pace that helps him to get away from players when it looks like he shouldn't.

"Then there was the added bonus - again like Jared - of the flexibility of where he can play.

"In the modern game, when you have a certain amount of bodies in your squad... you want to have guys who are multi-positional, which is a great asset to have and Will certainly fits that down to a T."

No bitterness and no regrets

Given how quickly he has become a part of the Ireland squad, it would be tempting to suggest that England missed a trick by not offering Addison a cap while he was consistently performing at Sale.

"I have always thought he was good enough for international rugby," admits Anglesea, who continues to track Addison's development.

Instead, Ireland have been able to call upon a player who is equally comfortable at wing, centre or full-back.

In his discussions with Addison before he signed for Ulster, Cunningham says there was never any hint of rancour over his lack of international progress: "There was no bitterness from Will about not getting a look-in with England or feeling that his time was up and it hadn't happened for him.

"I think, for a lot of players, sometimes a moment comes in their career where it's the right thing to do and maybe moving to Ulster was just the right timing for Will, for Ulster and ultimately for Ireland.

"I'm not sure anybody would have expected him to make such an immediate impression that he would get into the Ireland squad straight away but I think that's testament to how quickly he hit the ground running with us."

Wales coach Warren Gatland says his side can derail Ireland before the World Cup in Saturday's tournament warm-up match in Cardiff.

Ireland suffered a 57-15 hammering against England last weekend, while Wales are currently ranked number one side in the world.

"I was surprised by the Ireland result against England," said Gatland.

"This is professional sport and we can put a massive dent in their confidence, and derail them a little bit."

Ireland have never excelled in World Cups and have never gone past the quarter-final stage in the tournament.

"They are under an enormous amount of pressure back home with a lot of criticism given that they haven't progressed in World Cups further than they probably would have expected," said Gatland, who coached Ireland between 1998 and 2001.

"They're coming here knowing they've been criticised, they'll be hurting from last week.

"There are a lot of doubts in the coaches' minds about who their best players are.

"Some of their players are getting a bit older, is it a time to put some of the youngsters in? It's a massive game for Ireland that will answer a lot of questions.

"That's why I'm excited. It's a challenge for us."

Gatland also hopes Ireland will still be affected by Wales' 25-7 victory in March in Cardiff which sealed the Grand Slam and Six Nations title for Gatland's side.

"There could also be players involved who played in the Six Nations game and they'll be hurting from that as well," said Gatland.

"I couldn't ask for a better game for this group of players to have to go out there and perform."

'Ridiculous rankings'

Wales will lose their number one ranking if they do not beat Ireland this Saturday and could slip to fourth.

Joe Schmidt's men could even go top if they defeat Gatland's side by more than 15 points.

Current World Rugby vice-president and former Argentina scrum-half Agustin Pichot has criticised the ranking system, calling it ridiculous and said he was going to change the process.

Pichot highlighted that Wales are above New Zealand despite not having beaten the All Blacks since 1953.

Gatland has previously said the ranking was just a number and insisted Wales had not asked for the accolade.

"I'm quite happy to decline the position," said Gatland.

"We from now will forfeit our position. We didn't go in and apply for it. If he's not happy, then take it off us. It doesn't bother us.

"So we officially decline the position - thanks very much."