Head coach Gatland makes three changes to the side that beat the Springboks 22-17 last weekend, with Conor Murray and Chris Harris also coming into the starting XV to face the world champion on Sunday (AEST).

Vunipola replaces Rory Sutherland as he joins Luke Cowan-Dickie and Tadhg Furlong in the front row, while captain Alun Wyn Jones wins his 11th successive Lions Test cap as he partners Maro Itoje in an unchanged back row.

Murray comes in for Ali Price at scrum-half to partner Dan Biggar, while Harris is preferred to Elliot Daly to play alongside Robbie Henshaw in the centres.

The back three of Anthony Watson, Duhan van der Merwe and Stuart Hogg is unchanged, while Taulupe Faletau joins Sutherland, Price and Daly on the bench.

The Lions have only lost two series after winning the first Test, with the most recent occasion coming against Australia in 2001.

"As always, selection was incredibly tough," Gatland said. "However, we've made the changes we think are the right calls for the weekend's game.

"We feel we can go up another level from where we were in the first Test and I would expect us to improve.

"It's the biggest game on the Tour and we have to embrace the expectation that comes with it. As players and coaches, these are the games you want to be involved in. 

"We’re relishing the opportunity to face the Springboks again on Saturday and potentially seal a series win."

British and Irish Lions: Stuart Hogg, Anthony Watson, Chris Harris, Robbie Henshaw, Duhan van der Merwe, Dan Biggar, Conor Murray; Mako Vunipola, Luke Cowan-Dickie, Tadhg Furlong, Maro Itoje, Alun Wyn Jones (captain), Courtney Lawes, Tom Curry, Jack Conan.

Replacements: Ken Owens, Rory Sutherland, Kyle Sinckler, Tadhg Beirne, Taulupe Faletau, Ali Price, Owen Farrell, Elliot Daly.