"For all three of us - Christian Wade, Shane Williams and myself - I think you'll find that with something like this your body can just run on adrenalin. The sheer weight of what this game means to each and all of us is enough to give you motivation for a decade," said Barritt.
"The mind is stronger than the body. If you want to be there, you want to go out and do your bit for the side and not let the team down, you can achieve that.
"When Andy Farrell phoned me in the States, he did indicate to me I would be starting on Tuesday, so I just needed to get my head around that and be prepared. On the flight, I knew it was about getting my body-clock up to speed."
An intense training session at the North Sydney Oval blew away a few cobwebs for Barritt, Wade and Williams before they headed to Canberra with the team for the clash with Australian rugby's top Super Rugby franchise this year.
The rest of the day was spent doing homework on the class and plays and Tuesday night will be all about trying to maintain the Lions' unbeaten run on this special, 125th anniversary tour. The 47-17 win over the HSBC Waratahs made it five out of five, can the Lions make it a round half-dozen?
"The guys have performed fantastically, and it is up to us to carry the baton on Tuesday. It is a huge motivation for us to keep that winning momentum going, and if there is a good victory tomorrow it further adds to the confidence of the whole squad," said Barritt
"We just have to focus on this game and think of nothing else. I think as rugby players you live in a seven-day world - what happened last week is irrelevant to this week, and what happens next week is all dependent on this week.
"As a player you just go out there and give everything you can for the squad and try to help the team move forward."