After World Cup heartbreak in France, Ireland get their Six Nations defence underway in Marseille on Friday night.
Andy Farrell's men take on a France side, who like them, exited at the quarter-final stage. It will be a new era for Ireland, with former captain and long-term fly-half Johnny Sexton now retired.
In his place to start will be Munster's Jack Crowley, who was Sexton's back-up in the World Cup. Leinster's Ciarán Frawley is on the bench, while Harry Bryne will have to wait for his opportunity.
While quality is not an issue, there is a lack of experience, with Crowley set to make his Six Nations debut, and Frawley and Byrne having a combined three caps.
One man who has plenty of experience in the number 10 jersey for Ireland is Ronan O'Gara. Speaking ahead of the start of the Six Nations, O'Gara expects Crowley to take everything into his stride.
"They would be a lot more prepared than I was, I let the occasion get to me, I was a bag of nerves, a complete wreck. But that was probably par for the course at the time. 25 years later it’s a very different set-up. These guys are way more advanced in preparation, nutrition, psychological aspects of the game.
"What I like about Jack Crowley is I don’t get the impression he’s going to leave the seat available for someone. He has that element of confidence in him yet a lot of humility in him.
"What is so important at Test level is he doesn’t let mistakes eat at his mindset so he’ll continue to back his decision, continue to ask questions of the defence and that will stand him well.
"In that position you are only going to get better by the minutes you play. Yeah, he’s lacking minutes but I don’t think he’s lacking mental fortitude, that’s for sure."
Heading into the tournament, Ireland aren't the only country with changes at 10. Francewill go into the tournament without their star scrum-half Antoine Dupont, with Roman Ntamack also out injured.
The half back against Ireland will be Mathieu Jailbert at 10, with Maxime Lucu at scum-half.
England are without Owen Farrell after he decided to step away from international rugby, while Dan Biggar has retired from Wales duty.
While Byrne and Frawley may be lacking international experience, O'Gara has no concerns about the pair when their opportunity arises.
"Everyone has to start somewhere. It is the same as Richie McCaw when he came off the bench in Dublin, look at the career he had. These guys all start somewhere. T
"These guys aren’t experienced at the minute, that’s probably the negative, but in their heads, they are going I can’t wait to get on here and rip this up, because they probably feel hard done by, because I can offer a lot to the team.
"That’s the mindset of competitors. They need to take their place, and improve the team’s performance by 30 per cent."
