Goals from Kevin Behrens and Jordan Siebatcheu helped Union Berlin move 2-1 past stubborn Mainz and to extend their winning run to four games in the 19th round.
The 'Eisernen' gained the upper hand from the start and came close with 10 minutes gone as Mainz goalkeeper Finn Dahmen had to palm away Jerome Roussillon's attempt from 16 meters, reports Xinhua news agency.
The hosts continued on the front foot and opened the scoring 32 minutes into the clash after Paul Seguin's low cross to the far post found Behrens, who tapped home from very close range. Mainz took over after the restart whereas Union kept all its men behind the ball to secure the narrow win.
The visitors lacked in ideas and couldn't threaten Berlin's well-positioned defence but Mainz was still able to level the scores as Seguin handled the ball inside the box allowing Marcus Ingvartsen to restore parity with the subsequent penalty into the bottom right corner in the 78th minute.
Union coach Urs Fischer reacted on the equalizer and fielded Siebatcheu and Morten Thorsby. Fischer got rewarded for his substitutions as Thorsby headed into the path of Siebatcheu, who drilled the 2-1 winner past Dahmen with six minutes remaining.
With the result, Union Berlin capture the top spot at least for one night meanwhile Mainz suffered its second straight loss. "It was the expected difficult game with a lot of tackles, a lot of fouls, a lot of long balls.
The equalizer was unfortunate. The fact that my team fought back shows their mentality and will. But we couldn't have said anything if the game had ended in a draw," said Fischer.
Elsewhere, Borussia Dortmund are now equal on points with Bayern Munich as the "BVB" trashed 10-men Freiburg 5-1. Randal Kolo Muani's first-half brace secured Eintracht Frankfurt a 3-0 win over relegation-threatened Hertha Berlin.
Bochum reaped vital points in the relegation battle after cruising 5-2 past hapless Hoffenheim. Cologne held Leipzig to a goalless draw while last-placed Schalke clinched one point at Monchengladbach following a stalemate.