South African Joubert, who took charge of the 2011 World Cup final between New Zealand and France, will take the reins at Etihad Stadium. If the Lions win, they will secure a first Test series triumph since beating South Africa 2-1 in 1997.
"I rate him really highly as a referee. We have a good relationship with him," Gatland said. "What I like about Craig Joubert is that he's very personable and he has got a good feel for the game. He's honest. If he makes a mistake, he is the first person to come up to you, put his hand up and say that he made a mistake."
He added: "As a coach, you can't ask any more of a referee. They make mistakes, we make mistakes as coaches and players make mistakes. People putting their hand up and being prepared to admit that makes the conversation so much easier going forward.
"That is why I really like dealing with him because you just feel you are going out there with a guy who brings a human element to it.
"He is going to try to do his best. You are not going to get everything right, but if he does get a few things wrong he is open and honest about it, and that's brilliant."
Gatland, meanwhile, believes victory could prove a life-changing experience for his players. He readily accepts it is a case of seizing the moment and knows the spin-offs could be considerable if it becomes a case of mission accomplished.
"Potentially, for a lot of them (players), winning on Saturday has the potential to change a lot of their lives in a positive way, the opportunities that may create in a lot of different avenues," Gatland added. "We just need to make them aware of potentially how important Saturday is and the Test series is. It's that close.
"It (the weight of expectation) is something we are well aware of, but you can't let that weight of expectation dominate your performance in the game.
"It can't consume us and it is important it doesn't do that. We need to have that clarity of being mentally strong. If that weight of expectation is too heavy, you can sometimes go into your shell and it can constrict your play."