The 2009 Lions spent a week training together in Surrey prior to departure for South Africa and have now spent a further five days together since arriving in the Republic, but McGeechan admits that Saturday's opening fixture is a step into the unknown.
"I don't know what is going to come out on Saturday, in some respects," said McGeechan, who is embarking on his fifth Lions tour as a coach and his seventh in total.
"You look at any Lions team early on in a tour, it has that period where it is really starting to establish itself.
"We are ready to play, though. We'll have rough edges and things to work on, we know that, but I think everyone is ready for the game and wanting to play."
Players and coaches alike have spoken positively of how training has progressed during the initial stages of the tour, with plenty of 2009 Lions keen to highlight an impressive team spirit within the camp.
Now McGeechan is hopeful that such camaraderie will come to the fore on the pitch itself as the Lions look to get their adventure off to the best possible start at the Royal Bafokeng Sports Palace.
"You do the training, but then it is the players really starting to bring things out of each other. That's where you get the special relationship building in a Lions jersey," added McGeechan.
"You want them to be bringing the best out of each other. All these players have huge attributes, which is the reason why we selected them in the first place.
"What we are trying to do now is bring all those attributes to the fore in the combinations so it is an effective team performance that is drawing the best out of each player, and a little bit more."