With a record World Cup win wrapped up, Andy Farrell and Johnny Sexton could afford a smile or two.

"I heard he broke a few records today," said Farrell.

Cracking a wry smile, the coach turned to his captain: "What were the records, Johnny? The oldest player to ever play for Ireland?"

Speaking over the end of Farrell's playful barb, Sexton said: "I thought that was the last question."

With his fly-half sheepishly grinning to his left, Farrell went on to point out the other record that had tumbled in the sweltering Bordeaux heat - Sexton surpassing Ronan O'Gara's World Cup points mark for Ireland.

It was a light-hearted moment on which to end proceedings, but there was a clear, more stony-faced message to emerge from the Irish camp after the match: good start, but nothing more.

Yes, with 12 tries on the board, injuries avoided and a smooth reintegration for the skipper, Ireland can be pleased with their day's work as they swatted Romania aside.

But considering that everything Ireland have done over the past four years has been done with the World Cup in mind, Farrell and his players were never going to make any grand declarations about a big opening-weekend win over Romania.

No, for them, this was merely the start of the journey. Bigger tests lie ahead. Winning the first game does not necessarily lead to a smooth journey through the tournament. Ireland know all about that.

In fact, Farrell was quite happy to state his indifference to their first-half display, having conceded the opening try before hitting their stride to lead 33-8 at the break.

"I actually thought at half-time that we had a few things to sort out," said Farrell.

"We stopped the flow of our game quite a bit in regards to errors in our game, maybe discipline and we got a bit frantic with our communication."

Farrell followed that by saying he was pleased with a "composed" second-half display that featured seven tries as Ireland overwhelmed the lowest-ranked team in Pool B.

He was particularly satisfied by his team's desire to hunt a 12th try in the dying seconds - scored by Tadhg Beirne - instead of kicking the ball dead, a barometer of Ireland's mentality as they look to prove they are the best.

"I thought Hugo Keenan was going to kick it out but it was just as well Mack Hansen behaved like an Under-12 player and kept the ball alive," said Farrell.

"It was very important for the people we got off to a good start.

"Sixty thousand Irish homes have registered with World Rugby for tickets. Irish people coming from the UK, Europe or USA, what a journey it will be, I am more pleased for them.

"I hope the Irish people coming in the next few weeks can enjoy themselves. The journey has just started and I hope it will get a little bit better as well."

Sexton hungry for more after 24-point haul

Farrell was right, by the way. Sexton is the oldest player to play for Ireland. At 38 years and 58 days, he took that particular distinction off John Hayes.

But while he is well into his 39th year, Sexton showed why he remains crucial to this Ireland team.

Despite not having kicked a ball competitively in six months, he slotted seamlessly back into the Irish juggernaut on Saturday, demanding the best of himself and his team-mates.

His 24 points - his highest tally in a Test match - included two tries, but his kicking, vision and communicative skills laid the foundation for Ireland's red-letter day.

But still he was not satisfied. Farrell said the outside-half was "firing on all cylinders" but Sexton did not see it that way, his mind already drifting to a tougher match on the horizon against Tonga.

"Hopefully I can improve my performance for Tonga. It's going to be a much more difficult game, a different calibre of player," admitted Sexton who, to the relief of Irish fans, emerged for the second half unscathed after a Jason Tomane tackle hurt his hand as he touched down for his first try.

"We know the threat and it's a huge challenge for us."

For Ireland, it is job done. Time to move on to the next one. That means Tonga in Nantes next week.

Whether or not Farrell and Sexton will be joking around with each other after that one remains to be seen, but the early signs are promising as Ireland fix their eyes on rugby union's ultimate prize.