He has gone from fifth choice scrum half to Ireland's starting number 9 for their Pool C opener against the USA, with his calmness under pressure and array of passing and kicking skills obviously impressing the Ireland management.
Head coach Declan Kidney believes that Sunday's game in New Plymouth is the right fit for the promising 22-year-old from Patrickswell, County Limerick.
"Conor's been going well in training and we said we'd judge it off that. If we are to know more about him, now's the time to know," admitted Kidney.
"I think I'd be giving a mixed message if I thought we were doing anything with a view to next week (against Australia).
"It's purely on the back of what he's done, he deserves a go and even though it is his first start, it’s with a view to him doing well this week, and then whatever happens next week will happen.
"But we think he's good enough to start for us. It's a big call giving him his first start in the Rugby World Cup, but what he's been doing I believe merits it."
Giving his assessment of Ireland's latest international player, captain Brian O'Driscoll said: "He's a confident young man and has shown great form in training.
"I think he has translated that well onto the pitch when he has gotten his opportunities. I have no doubt he is up to the challenge."
It will be Murray's third cap and first alongside fellow World Cup debutant Jonathan Sexton at half-back. The pair played together in the final 18 minutes of the recent warm-up game against England.
"With every minute they will have together on the pitch, they'll improve. I wouldn't envisage any difficulties," insisted O'Driscoll.
"I'll expect them to do what half backs do best and that's boss things, especially bossing the forwards around the place."
Competition for places is particularly intense out wide in the backs. Andrew Trimble, who had some eye-catching displays during the warm-up schedule, is unfortunate to miss out as two more tournament newcomers, Tommy Bowe and Keith Earls, get the wing spots.
Explaining the decision there, Kidney said: "You've three wingers that are going well for us. Of Keith's three (recent) games, two have been in the centre and I just felt that it was right to give him the go on the wing because he's only had one run on the wing and he's done well for us on the wing.
"Tommy (Bowe) has just come back from injury and had one game under his belt, and that's why Andrew is missing out. He's unlucky, he’s done very well for us in all four games, it's just a good position for us to be in."
Notably, Rob Kearney and Sean O'Brien have been held back to give them extra time to get fully fit following their respective groin and knee injuries.
Shane Jennings will start at openside flanker, slotting into a back row without any World Cup experience, while the fit-again Geordan Murphy will add experience to the back-three.
"Sean is fit to play, medically he has been given the okay. But I've seen injuries like that before and he'll benefit from getting absolute fitness back," added the Corkman, speaking at the team hotel in New Plymouth.
"I believe in the squad too. Shane Jennings has been going well in training and has a bit of match-time under his belt from last month.
"With Rob, I want him to get up to full speed a bit more often, and once he does that he's shown he can just come in (as he did against Scotland France last month). The fact that he's not playing doesn't rule him out by any means for next week."
Ireland have played the USA on six occasions at Test level, posting six wins including a 27-10 success in Santa Clara two years ago which saw stand-in captain Rory Best lift the Setanta Challenge Cup.
There will be much more on the line at Stadium Taranaki on Sunday, and the Ireland camp has acknowledged that the 10th anniversary of the 9/11 terrorist attacks will have the American players 'charged up' for a big performance.
There is also the matter of Eddie O'Sullivan, Ireland's boss at the last Rugby World Cup and winner of three Triple Crowns, being in the opposing corner.
Looking forward to getting his side's World Cup campaign underway, Kidney anticipated: "It will be a tough match. Eddie obviously knows the (Ireland) players very well, will know strengths, will know weaknesses.
"He's a top class coach and this game will mean an awful lot to him. It's been designated from a long time out.
"With the date that's in it there'll be a lot of emotion floating around and he'll be a good man to keep a lid on that to use that in a good way too. I think (the selected team) is good enough to play a match for us and hopefully get a result."
Follow the Ireland team in New Zealand on www.twitter.com/irfurugby.