Now firmly back in coach Eddie O'Sullivan's for Sunday's must-win clash with Argentina, partly due to a shoulder injury to Dempsey, full-back Murphy is happy to take the chance with both hands.
"There are many emotions that you feel going into a game like this one at the weekend but Iâ00ll be just very pleased to be getting a start. Everyone knows what happened to me at the last World Cup (with the broken leg) and this hasn't been a successful World Cup for me either, so Iâ00m just looking forward to having a run on Sunday," Murphy explained.
"I'm back in the side this week because Girv's injured. Itâ00s a horrible thing to say but Iâ00m happy to be starting. I'm obviously disappointed for him but it gives me a shot."
Murphy is well aware of what is at stake this weekend at the Parc des Princes - Ireland require a bonus point win over the Pumas with at least an eight-point winning margin to qualify for the quarter-finals - and he is hoping Ireland can be in a position in the last 20 minutes to hunt for that bonus point-clinching fourth try.
"It's a massive game for us. Thereâ00s a lot of pressure, both from an individual point of view and a team point of view. Weâ00ve got a massive mountain to climb but at least we have a target I suppose in that we know what we have to do.
â0But we canâ00t go out and try to get four tries from the beginning. We have to go out and try to build a lead. Most of the guys have been involved in games before where you have to get a bonus point and the way that works is going out and getting a lead," he admitted.
"If you can get an early try, that's great because then you start working on the second try. But it's only when you get to the last 20 minutes that the bonus point becomes a real issue."
The Leicester Tigers star has tried his best to remain upbeat despite failing to force his way into the Irish team until the fourth and final pool game. So how did he cope with the disappointment of missing out on selection for the first three matches?
"At first you withdraw into yourself for a little while. You feel a little bit down. And youâ00re a bit like 'oh God, what next?' But in a team environment you try to remain upbeat for the rest of the guys.
"It's very easy to walk around with your head down, sulking, but that's not good for the team. So once you get a couple of the guys slapping you on the back saying 'hard luck', you kind of think 'right, Iâ00ve got to move on here and just smile," he said.
As soon as Murphy's name was missing from the Ireland squad for the French game, rumours began to spread about the 29-year-old quitting the Irish camp and turning his back on the squad. But as with most rumours in sporting circles, they had no foundation whatsoever.
The player himself explained: "I don't know where it all came from, to be honest. The first I heard of it was I was having dinner last Monday and someone sort of pulled me aside and said that theyâ00d heard that I was heading home or whatever.
"Obviously, there was no truth in that whatsoever so I didnâ00t take it too seriously at the time. I just thought it was a silly rumour, but when I got back to my room Iâ00d quite a few texts and missed calls, with people saying stuff like â00what are you doing?â00
"So, then I had to assure people that I was still in the team hotel and I hadnâ00t gone anywhere! I wouldnâ00t do something like that. Itâ00s a team sport. Obviously, I was disappointed but everyone in the 30-man squad feels that they can add something to the team," he added.
So, youâ00re always disappointed when you get left out. But I just wouldn't throw the toys out of the pram and walk out on the guys in a tournament like this."