With none of the sport's 'big three' in the semi-finals, the US Open men's singles is wide open in New York.

German fifth seed Alexander Zverev takes on Spanish 20th seed Pablo Carreno Busta in Friday's first semi-final at 21:00 BST, with Austrian second seed Dominic Thiem facing Russian third seed Daniil Medvedev afterwards.

Switzerland's Stan Wawrinka was the last man other than Federer, Nadal and Djokovic to secure a Grand Slam title when he triumphed at the 2016 US Open. There is about to be a first new men's major winner since Croatia's Marin Cilic in 2014.

So let's have a look at the four contenders...

Pablo Carreno Busta (Spain), 20th seed

Carreno Busta's run to the US Open semi-finals will be remembered for one thing - Novak Djokovic's disqualification.

The Spanish 20th seed had just broke for a 6-5 lead in the opening set of their fourth-round match when top seed Djokovic hit a line judge with a ball.

Carreno Busta will have been thankful for the extra rest that walkover brought, as the 29-year-old needed five sets and four hours to see off Denis Shapovalov two days later in their quarter-final.

It is the second time the world number 27 has reached this stage at the US Open, losing his only other Grand Slam semi-final to South African Kevin Anderson at Flushing Meadows in 2017.

As well as that run, Carreno Busta has enjoyed other notable success on American hard courts, having reached the semi-finals at Indian Wells and Miami in recent years.

"It's very important to be back in the semi-finals of the US Open," said Carreno Busta, who reached a career-high ranking of 10th in the world after his run in 2017 - when he also made it to the French Open quarter-finals.

"When I reached the quarter-finals in Roland Garros in 2017, it was amazing. Then I made a semi-finals here. It was unbelievable."

Alexander Zverev (Germany), fifth seed

Fifth seed Zverev is into the US Open semi-finals for the first time, having only once reached this stage of a Grand Slam before, when he lost to Thiem at the Australian Open earlier this year.

The 23-year-old has long been touted as one of the next generation of players with the potential to break the dominance of the 'big three', and beat both Roger Federer and Novak Djokovic on his way to winning the ATP Finals in 2018.

The 6ft 6in German has 11 singles titles to his name and reached a career-high third in the world in 2017.

As the highest-ranked player left on his side of the draw, Zverev will be expected to reach a first Grand Slam final.

But he will have to improve on his second serve percentage if he is to be successful, racking up 12 double faults in his quarter-final victory over Croatia's Borna Coric, while the youngster's temperament has also been called into question on occasions.

"I still think that I can play better, which only gives me confidence because I'm in the semi-finals and I still feel like I can improve," Zverev said after beating Coric.

"I have just made back-to-back semis and I'm still in the tournament, so I'm not done yet.

"I have got more experience and maybe a little bit more calmer in Grand Slams than I have been in the past."

Dominic Thiem (Austria), second seed

It was not a case of 'third time lucky' for Thiem when he lost to Djokovic in the Australian Open final in February.

That was his third defeat in a Grand Slam final as he chased that elusive first major, having lost to Nadal in the previous two years at the French Open.

With Nadal not going to New York and Djokovic making an undignified exit, 27-year-old Thiem seems to have grown into the role as the highest seed left in the men's draw.

The Austrian says he intends to use the experiences of those previous defeats in major finals to help him finally become the first Grand Slam champion born in the 1990s.

"These are great memories, in the Slams I went deep, even though I lost three finals," said Thiem.

"If I think back at these tournaments, they were great to me. I lost finals against all-time greats. I think they were great matches.

"I love to look back at them and of course look back at them now and check out what I can improve. I hope these experiences help me also in this US Open."

Daniil Medvedev (Russia), third seed

Like Thiem, Medvedev also has the experience of playing in a Grand Slam final - having lost to Nadal in a memorable finish to last year's US Open.

The 24-year-old Russian trailed by two sets and a break, then launched a exhilarating comeback before losing in a five-set battle lasting nearly five hours.

Even though that ultimately ended in defeat, Medvedev won over plenty of new fans with his relentless returning, superb shot-making and a quirky sense of humour.

Undoubtedly he would have impressed countless more this fans had the New York crowd been able to watch him in the flesh.

Medvedev is the only man left in the draw who has yet to drop a single set in the tournament.

A strong service game has been the bedrock of his progression to the last four, winning 96% of those games and facing just nine break points in his previous five matches.

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