Gatland has made two changes to a pack that lost the battle of the breakdown in Auckland for a match the tourists must win to retain a chance of winning a test series in New Zealand for the first time since 1971.
Warburton moves up from the bench to blindside flanker in an otherwise unchanged back row in place of Ireland's Peter O'Mahony, who captained the side in the series opener but has been dropped from the matchday squad.
As expected, Maro Itoje was brought into the second row but in a minor surprise he will lock with Welshman Alun Wyn Jones, who had a poor first test but is preferred as a lineout organiser to George Kruis.
Kruis also drops out of the matchday squad with his England team mate Courtney Lawes offered the chance to make an impact from the bench along with Irish loose forward CJ Stander.
"We saw Maro's impact in the first test and he will bring an edge and a physicality, as will Sam Warburton in terms of pressure on the ball," Gatland said in a news release.
"It's tough on Peter O'Mahony who has done a brilliant job for us. We felt that CJ Stander's ball carrying and defence was the right choice for the bench."
Ireland's Jonny Sexton will start at flyhalf with Owen Farrell moving to inside centre in place of Ben Te'o to give the Lions twin playmakers as they look to carve out try-scoring opportunities.
"Both have played well and it gives us that attacking option in the 10-12 channel," Gatland added.
"We created opportunities in the first test and there were a few that we didn't finish."
Te'o, who kept Sonny Bill Williams relatively quiet in the first test, drops to the bench, where England's Jack Nowell offers cover for the back three instead of Leigh Halfpenny, Player of the Series when the Lions beat Australia in 2013.
"There were lots of positives from the first test but we were disappointed that we put ourselves in a position to put the All Blacks under pressure and to get back into the game and we let it slip," Gatland added.
"For the players retained from the first test it's an opportunity for them to step up and to show an improvement ... and you have another group coming in who are also desperate to seize their chance."
The Lions earlier announced that winger George North and centre Robbie Henshaw had been ruled out of the remainder of the tour after suffering injuries in the final midweek match.
Team: 15-Liam Williams, 14-Anthony Watson, 13-Jonathan Davies, 12-Owen Farrell, 11-Elliot Daly, 10-Jonathan Sexton, 9-Conor Murray, 8-Taulupe Faletau, 7-Sean O'Brien, 6-Sam Warburton(captain), 5-Alun Wyn Jones, 4-Maro Itoje, 3-Tadhg Furlong, 2-Jamie George, 1-Mako Vunipola.
Replacements: 16-Ken Owens, 17-Jack McGrath, 18-Kyle Sinckler, 19-Courtney Lawes, 20-CJ Stander, 21-Rhys Webb, 22-Ben Te'o, 23-Jack Nowell