Robert Lewandowski's last-minute penalty gave Bayern Munich a 13th victory in a row as they beat Wolfsburg to go 21 points clear at the top of the Bundesliga.

Daniel Didavi gave the struggling hosts a shock lead and Bayern's Arjen Robben had a penalty saved by Koen Casteels.

Sandro Wagner headed in Robben's cross to equalise for the champions.

And substitute Lewandowski scored the winner from the spot after teenager Gian-Luca Itter fouled Robben.

Bayern named several key players on the bench, including Lewandowski, Mats Hummels and David Alaba, with Tuesday's home Champions League last-16 first leg against Besiktas in mind.