Bayern Munich have maintained their 20-point lead at the top of the Bundesliga with a narrow 2-1 away victory over Bayer Leverkusen.

The visitors had the better of the chances in the opening 30 minutes, with Javi Martinez heading Arjen Robben's free kick over the crossbar before the Dutchman saw his header cleared off the line by Gonzalo Castro.

The league leaders eventually made the breakthrough eight minutes from the half-time interval when Mario Gomez was set up by Xherdan Shaqiri to burst into the Bayer penalty area and score from close range.

The home side showed more intensity and determination after the break, Sidney Sam volleying just over the Bayern crossbar before Rafinha cleared a Stefan Kiessling's cross just in time.

Bayer's effort finally paid off in the 75th minute when Simon Rolfes tapped in Sebastian Boenisch's free kick.

Claudio Pizarro had a good chance to restore Bayern's lead just two minutes later, but he dragged his shot wide.

However, the Bavarian giants secured the win three minutes from normal time, Philipp Wollscheid scoring an own goal.