British and Irish Lions centre Brian O'Driscoll has insisted that the deciding Test against Australia will be just as mentally challenging as it will be physically.

The Wallabies levelled the series on Saturday in Melbourne with a narrow 16-15 victory that cancelled out the Lions' 23-21 win the weekend before in Brisbane.

"It was a really good analogy from Jonny Sexton sitting on a plane today saying it's rare after a cup final that you get the chance to relive it again and put the things you did wrong, right," O'Driscoll told reporters.

"There is always a mental toll in games of this magnitude. Thankfully, you do get seven days to try to get over one game and have the building process for the next one. This game is very much mental as much as it is physical, and all the more so when you play opposition three weeks in a row.

"You definitely get to know each other an awful lot more and you are almost anticipating certain things to happen. There is an element of trying to out-think the opposition."

The third Test takes place on Saturday in Sydney.