Berlin (AFP) - Union Berlin's slim hopes of a remarkable Bundesliga title were dented by a 0-0 draw at home against Bayer Leverkusen on Saturday.
Unbeaten at home in the league this season, Union's best chance came midway through the second half when Sheraldo Becker hit a Jerome Roussillon cross wide of the post.
A win would have taken Union three points behind first-placed Borussia Dortmund in just their fourth season of top division football.
Despite the draw, Union remain third and on course for a maiden Champions League placing with four matchdays remaining.
Describing Leverkusen, who are unbeaten in 14 matches, "the most in-form team in the league", Union manager Urs Fischer praised his side's "intense, great performance" in "neutralising" the visitors.
The stalemate also hurt Leverkusen's narrow chances of qualifying for the Champions League, with the Xabi Alonso-coached side now eight points outside the top four.
"Union has not lost here yet this season, and we could sense why," said Alonso.
In Saturday's late game, second-last Schalke picked up a crucial three points in their battle to beat the drop, Dominick Drexler scoring in the second minute of injury time for a 2-1 home win over Werder Bremen.
Trailing 1-0 due to Marvin Ducksch's fourth goal in two games with 10 minutes remaining, Liverpool loanee Sepp van den Berg slammed in a low strike to level the scores.
Drexler finished off a length-of-the-field move with the clock winding down, to send Schalke five clear of last-placed Hertha and one point from safety with four games remaining.
Despite the loss, Bremen remain seven points clear of the relegation spots in 12th place.
Freiburg flying
Elsewhere, Freiburg solidified their chances of following Union to a first-ever Champions League qualification, a second-half Ritsu Doan tap-in taking them to a 1-0 win away at Cologne.
The win took Freiburg to fourth, behind Union on goal difference, two clear of RB Leipzig who also won 1-0 on Saturday.
Leipzig beat Hoffenheim thanks to Christopher Nkunku's first league goal since November.
Nkunku, handed his first start since returning from injury, collected a pass from Emil Forsberg and sent a left-footed finish into the right corner of the goal, chalking up his 13th goal in 21 league matches this season.
Leipzig are fifth, six points ahead of Leverkusen.
Stuttgart leapfrogged Bochum out of the relegation places with a 2-1 home win over a ten-man Borussia Moenchengladbach.
The home side took the lead thanks to a classy Serhou Guirassy back-heel finish after 22 minutes.
Gladbach's Julian Weigl converted a penalty with 22 minutes remaining but Stuttgart were awarded a spot kick of their own five minutes later when Ko Itakura was shown a straight red for bringing down Tiago Tomas.
Stuttgart's Tanguy Coulibaly converted the penalty to give his side a welcome boost ahead of Wednesday's German Cup semi-final against Eintracht Frankfurt.
Frankfurt drew 1-1 at home against Augsburg, extending their winless run to nine matches and likely extinguishing any slim hopes the Europa League holders have of a return to Europe.
