Bundesliga leaders RB Leipzig suffered their first defeat since October as second-half goals by right-back Almamy Toure and winger Filip Kostic gave Eintracht Frankfurt a 2-0 home win on Saturday.
Leipzig's stumble in Frankfurt opens the door for defending champions Bayern Munich, who are third, but can cut the gap at the top to just a point if they beat fifth-placed Schalke later at the Allianz Arena.
It was Leipzig's first defeat in 14 games in all competitions since losing 2-1 to Freiburg at the end of October and they are now just two points clear of second-placed Moenchengladbach.
After squandering 12 clear chances, with Germany striker Timo Werner the main culprit, Leipzig were punished for their lack of finishing.
Frankfurt took the lead against the run of play through Toure's stunning effort just after the break as he converted only his team's second clear chance.
A throw on from the left was flicked onto Toure, whose half-volley flew into the top corner on 48 minutes with Leipzig goalkeeper Peter Gulacsi at full stretch.
Leipzig coach Julian Nagelsmann reacted by boosting the attack, taking off midfielders Konrad Laimer and Tyler Adams and bringing on striker Yussuf Poulsen and ex-Everton winger Ademola Lookman.
Leipzig grew ever more desperate in their efforts to equalise and with space opening up, Kostic, who hit the crossbar twice in last weekend's 2-1 win over Hoffenheim, tucked home their second goal in the 94th minute to delight the Frankfurt crowd.
Elsewhere in the title race, Moenchengladbach came from behind at home to poach a 3-1 win at Mainz to leap-frog Bayern into second in the table.
After Sweden forward Robin Quaison gave Mainz an early lead, Gladbach's French striker Plea banged in two goals either side of half-time before midfield replacement Florian Neuhaus grabbed a late third to rescue the three points.
Jurgen Klinsmann's Hertha Berlin bounced back from their 4-0 thumping at home to Bayern last Sunday which left them hovering just above the relegation places with a 2-1 win at Wolfsburg thanks to goals by replacement forward Dodi Lukebakio and defender Jordan Torunarigha.
Paderborn moved off the bottom of the table with a 2-0 win at Freiburg, thanks to goals by winger Christopher Antwi-Adjei and a penalty by midfielder Abdelhamid Sabiri.
However, the visitors finished with 10 men when left-back Jamilu Collins was sent off with half an hour to go for a second yellow card.
Union Berlin bounced back from their defeat at Leipzig with a 2-0 home win over Augsburg thanks to goals by defender Neven Subotic and attacking midfielder Marcus Ingvartsen.
Dortmund are fourth in the table after routing Cologne 5-1 on Friday with Norwegian wunderkind Erling Braut Haaland scoring twice off the bench to give him with five goals in just two games after a hat-trick on his debut last weekend.