(CNN) -- Schalke claimed top spot in the Bundesliga on Saturday as previous leaders Bayern Munich suffered a second successive league defeat ahead of next week's Champions League quarterfinals.
Former Germany striker Kevin Kuranyi netted both goals as Schalke won 2-0 at third-placed Bayer Leverkusen to move two points ahead of Bayern, with the top two teams to meet next weekend as the title race moves into the final six games.
Kuranyi's first-half double took him to a German league leading 17 goals this season, but he is still unlikely to win a World Cup place after being dropped for walking out on the national team during a qualifier against Russia.
Leverkusen were left five points behind Schalke after suffering a third league defeat this season.
Bayern, beaten at Eintracht Frankfurt last weekend, were this time upset 2-1 at home by Stuttgart in a demoralizing defeat before Tuesday's European clash with Manchester United.
The Bavarian giants, who beat Schalke 1-0 in extra-time in midweek to reach a 17th German Cup final, took a 32nd-minute lead through Croatia striker Ivica Olic despite opting to rest in-form Dutch forward Arjen Robben and France star Franck Ribery.
However, Christian Trasch's deflected shot beat goalkeeper Hans-Jorg Butt to level four minutes before halftime.
Bayern coach Louis Van Gaal brought on both Robben and Ribery after the break, but his side went behind five minutes later as Romanian striker Ciprian Marica headed home from close range from Cacau's cross.
The win lifted Stuttgart up into seventh place and boosted Christian Gross's team's hopes of winning a European place for next season.
Borussia Dortmund retained fourth place despite being held to a 0-0 draw at bottom club Hertha Berlin, who had a 79th-minute effort by striker Theofanis Gekas ruled out for offside.
Werder Bremen, who will defend their German Cup title against Bayern, moved to within a point of Dortmund in fifth after beating Nuremberg 4-2 despite having captain Torsten Frings sent off with seven minutes to play.
Bremen led 3-0 after 36 minutes thanks to a headed brace from Per Mertesacker and another goal by Tim Borowski, but the fourth-from-bottom visitors hit back in the second half through Mike Frantz and penalty to Maxim Chupo-Moting.
Frings was red-carded for elbowing an opponent, but Clemens Fritz settled home nerves from a corner three minutes into time added on.
Champions Wolfsburg won 2-0 at Mainz with two late goals from striker Edin Dzeko to go ninth, a point behind Frankfurt -- who beat Bochum 2-1 on Friday.
Cologne eased their relegation worries as a 4-1 trouncing of Hanover which put them eight points clear of the third-bottom team.