"It's awesome. I'm dying to get on the pitch and it can't come quick enough," admitted the Welsh back row ace. "I've loved it even though I haven't been able to play and it has been pretty special being able to go to the games as a spectator.
"I'm still among the boys at training and in the gym and I don't feel left out at all. But now I've finally got my chance on Saturday. I have been thinking about this game for the last week or so and I'm desperate to get on the pitch and have a decent game.
"It has been the best three weeks of my career since the squad got together. It has just been tough to watch the other boys get a Lions jersey when I haven't got one yet.
"It will be a massive tick in the box career wise to say I have started for the Lions. It will feel like a weight off my shoulders because it is something I've wanted to achieve for a long time."
The tour may finally be getting underway for Warburton, but he knows the hard work is only just beginning. The six back row men who have played before him have all had stand-out matches and there is no easy pathway for any of the Lions' 'Magnificent Seven' into the Test team.
Not that Warburton has had it any other way during his career - nor wants it any other way. Competition for places, he says, brings out the best in him and he wants to be driven to produce his absolute best.
Justin has been playing well or the last two or three years, so I've been in this position for the majority of my playing career, which is what you want. I thought Sean had a great game and stood out, just as Jamie Heaslip did. All the back row players have done very well which I'm sure is going to make selection very tough.
"I've been in that position for the majority of my playing career which is what you want really. Looking at the seven back rowers we have picked they are all top class players and I hope I get the chance to play with them all," said Warburton.
"I obviously know all the Welsh boys well, but I've always wanted to play with Sean O'Brien because I have always found him very tough to play against and he is someone I have a lot of respect for, as with Jamie Heaslip and Tom Croft.
"I always thought the back row would be one of the strongest positions for the Lions, especially when you see the likes of Chris Robshaw and Kelly Brown not selected and someone of Stephen Ferris' class ruled out through injury.
"But it's great they've all played so well to date because it just makes the competition even harder and it is those three Test spots that we everyone is chasing."