Jamie Roberts has no illusions about the task at hand after replacing veteran Ireland centre Brian O'Driscoll for the third and deciding Test against Australia.
"A thousand people have said it before me, and thousands will say it again," Roberts said yesterday. "He is one of the greatest players to have played this game."
But O'Driscoll was not named in the 23-man line-up by coach Warren Gatland for the Sydney Test on Saturday as the visitors attempt to win their first series since the 2-1 win over South Africa in 1997.
Roberts was among those most shocked that O'Driscoll, touted as possible captain for the deciding Test due to the injury absence of Sam Warburton, was not even in the match day 22, let alone the starting line-up.
"Surprised is not the right word," Roberts said.
"Warren has made some big calls and ultimately you respect the coach's decision. He's picked the team that he feels will win Saturday, whether that includes Brian O'Driscoll or not. A lot of very good players missed out on playing. It shows you how competitive the environment is."
Roberts was thankful that a hamstring injury sustained in a tour match against New South Wales Waratahs on June 15 did not end his tour.
"It's been very tough," the Welshman said. "First and foremost thanks for the medical team for getting me here. I thought I'd be on my way home.
I had a scan, and they said we're going to keep you on tour, we're going to keep faith in you. Now it's great to be playing a part in the big day on Saturday."
Roberts said O'Driscoll was a class act in reaction to his omission from the squad.
"It was the most nerve-racking team selection I have ever had in my career," Roberts said. "To show what kind of guy he was, he [O'Driscoll] was the first guy to come up to me after training today and say 'do you want to do any extras?'"
In 2009, when the Lions lost the deciding match to South Africa, Roberts was not in the line-up.
"I had injured my wrist in the second Test and couldn't play in the third one," Roberts said.
"So to play in the deciding Test, probably that and a World Cup final is the ultimate; it's a great stage."
Roberts is one of six changes to the side that will be led by Alun Wyn Jones in the absence of injured captain Warburton.
Jonathan Davies will start at outside centre, two of 10 Welshmen in the starting line-up.
Toby Faletau comes in at No 8 for Ireland's Jamie Heaslip and Mike Phillips, who played in the first Test win but was rested for the second Test defeat because of concerns about his knee, returns at scrum-half in place of England's Ben Youngs. Irishman Sean O'Brien replaces Warburton at openside flanker.