Ireland head coach Joe Schmidt says he has the utmost faith in Jack Carty, who is set to start just his second ever Test match this weekend.
The Connacht out-half replaces Jonathan Sexton for Saturday's World Cup game with Japan in one of four changes from the win over Scotland.
Joey Carbery provides cover on the bench, Rob Kearney returns at full-back, Keith Earls is named on the wing while Chris Farrell comes into the centre for Bundee Aki.
Schmidt feels there's plenty to Carty's game to cause Japan trouble.
"He's very calm, he doesn't get ruffled easily. He doesn't get distracted by an error he might make or distracted by people trying to put pressure on him. He stays in the zone incredibly well," he said.
"For us, with Jack, there's a lot of confidence from the coaching staff and from the players as well.
"So, the spectrum of skills he brings; obviously I've mentioned his angled kicking game, for us to get out of our '22 on the weekend, he put through that ball on the ground. I think he's got a bit of a running game, he takes the ball to the line like he did against Wales and links up with the players.
"That's another attacking threat he brings.
"Defensively, we've been really happy with the progress he's made in Connacht in recent times and now with the national side."
Conor Murray will partner the Athlone man in the half-backs on Saturday and he feels the 28-year-old is ready for the occasion:
"He's quite a calm character, Jack, which is good to have outside you, like anyone that comes into the set-up there's a pressure to learn and step up on you and he's responded really well to that.
"He's got to grips with the way we play, the tactics and phase-calls and what's expected of him.
"That laid-back nature has aided him in coming into an environment like this and learning off the likes of Johnny and Joey, who is actually younger than him but has been around the set-up for a while.
"So, yeah, I'm excited to play with Jack. He takes it in his stride, he's played really well any time he's been given the chance whether in the Six Nations or the summer series, coming over here and coming on last weekend he did really well".
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