Thiago Alcantara's second-half equaliser rescued Bayern Munich in Saturday's 2-2 draw at home to Mainz as the runaway Bundesliga leaders had to twice come from behind.

Having bowed out of the Champions League quarter-finals 6-3 on aggregate following Tuesday's 4-2 second-leg defeat at Real Madrid, the draw caps a week to forget for Bayern, who are winless in their last four games.

Relegation-threatened Mainz came close to another shock win in Munich, but Bayern extended their unbeaten home run in the league to 20 matches dating back to March 2016, when they lost 2-1 to Mainz.

Spain star Thiago hit the equaliser 17 minutes from time to sneak the draw with Mainz just one point from the relegation places with four games left.

Second-placed RB Leipzig can cut Bayern's lead to six points by winning at Schalke on Sunday.

Leipzig will host Carlo Ancelotti's Bayern on the penultimate weekend on May 13.

Mainz took the lead just three minutes after kick-off at the Allianz Arena.

Arturo Vidal lost the ball on the edge of Bayern area and ex-Barcelona midfielder Bojan Krkic snapped up possession to slot his first goal for Mainz to stun the home crowd.

Normal service was resumed when Arjen Robben sprinted onto Franck Ribery's superb pass and rifled home Bayern's first equaliser on 16 minutes.

Munich then lost Austria defender David Alaba, clutching his thigh, moments later.

Bayern's problems were compounded when his replacement Joshua Kimmich fouled Mainz's Japan striker Yoshinori Muto in the area.

Bayern's goalkeeper Manuel Neuer is sidelined with a foot fracture for the rest of the season and his replacement Sven Ulreich could not stop Daniel Brosinski's penalty on 41 minutes to put Mainz 2-1 up at the break.

Bayern finally made their 75 percent possession count with Thiago equaliser from 17 metres out.

Elsewhere, Germany striker Max Kruse scored all four goals to cancel out Pascal Gross' penalty and Dario Lezcano's goal for relegation-threatened Ingolstadt in Werder Bremen's 4-2 away win to climb into the top six.

Kruse is playing his way into Germany's squad for June's Confederations Cup with nine goals in his last seven league games.

Ingolstadt remain four points from Hamburg in 16th place, which carries a two-legged relegation play-off at the end of the season.

Hertha Berlin stay fifth -- and on course for a Europa League berth next season -- after Vedad Ibisevic's second-half goal sealed their 1-0 win over Wolfsburg, who drop to 14th.

The 2009 Bundesliga champions and 2015 German Cup winners are just one point from the bottom three.

Bottom side Darmstadt delayed their impending relegation by another week with a 2-1 win at Hamburg as captain Aytac Sulu and striker Felix Platte netted for the visitors in the first three minutes after the break.

However, Darmstadt, coached by ex-Germany midfielder Torsten Frings, are 12 points from safety with four games left and have only a mathematical chance of staying up.

Eintracht Frankfurt picked up their first win in eight games as Mexico midfielder Marco Fabian netted two late goals in their 3-1 comeback win at Augsburg.