BERLIN (AP) -- Schalke missed the chance to join Borussia Dortmund at the top of the Bundesliga Saturday with a 1-1 draw at home to Mainz.
Mohamed Zidan gave Mainz the lead in the 15th minute before Schalke winter signing Chinedu Obasi pulled one back in the 59th.
Borussia Moenchengladbach failed to take advantage and remains a point behind Schalke in fourth after being held 0-0 at Wolfsburg.
Martin Harnik scored an 89th-minute equalizer for Stuttgart to end its four-game losing steak in a 2-2 draw at Leverkusen, where both sides had a player sent off.
Elsewhere, Augsburg drew 2-2 at Hoffenheim, and Hannover won 1-0 at Hertha Berlin, which also had a player sent off.
Bayern Munich could reclaim the league lead on goal difference from Dortmund with a win at Hamburger SV later Saturday.
Defending champion Dortmund put the pressure on its rivals Friday with a 2-0 win at Nuremberg to stretch its unbeaten run to 14 games.
Schalke started sluggishly, and Zidan marked his return to Mainz after his winter transfer from Dortmund by reaching a long Radoslav Zabavnik cross to volley in from close range.
Despite boasting an attacking wealth of options including Raul Gonzalez, Julian Draxler and Ciprian Marica, Schalke's first shot on goal only came in the 42nd from Klaus Jan Huntelaar.
The home side improved after the break, and Obasi deservedly equalized when he eluded Zdenek Pospech with a couple of stepovers before beating Christian Wetklo at the near post.
Moenchengladbach had two goals ruled out for offside in the first half, with Mike Hanke unlucky to have his 37th minute effort ruled out, as TV replays showed the former Wolfsburg forward in line with the defense before he fired past Diego Benaglio.
Marco Reus should have scored in the 69th, the Moenchengladbach winger missing a great chance when he only had Benaglio to beat.
In Leverkusen, former Germany captain Michael Ballack stayed on the bench for the second game in a row following criticism from club management.
Stefan Kiessling fired the home side ahead from a rebound in the 11th, before Julian Schieber equalized from an indirect free kick in the 23rd.
Stuttgart captain Serdar Tasci bundled Lars Bender over after the break, and Leverkusen captain Simon Rolfes took full advantage to score from the penalty spot in the 47th.
Leverkusen defender Michal Kadlec was sent off in the 63rd, earning his second yellow card for a foul on Cacau five minutes after earning his first.
Cacau set up Harnik's late equalizer and there was still time for Cristian Molinaro to be somewhat unluckily sent off for catching Andre Schuerrle's face in injury time as he was going for the ball.
Mohammed Abdellaoue scored his 11th goal of the season for Hannover with a stunning strike in the 68th, increasing the pressure on Hertha coach Michael Skibbe.
Skibbe has lost all three games since taking over from the sacked Markus Babbel.
Hertha, which hasn't won in nine Bundesliga games, also had Sebastian Neumann sent off for a second yellow card in the 75th.
Augsburg striker Sascha Moelders ended 347 minutes without scoring when he put the visitors ahead against Hoffenheim the 31st, but Hoffenheim striker Peniel Mlapa then scored his first goal of the season to equalize in the 38th.
Sejad Salihovic put the home side ahead from the penalty spot in the 51st, before Sebastian Langkamp equalized again in the 72nd with a header from a corner.