Union Berlin halted a three-match losing run and dented RB Leipzig's title challenge with a composed 3-1 home victory founded on defensive discipline and clinical finishing at the Stadion An der Alten Forsterei on Friday.

Leipzig, starting the evening second in the Bundesliga, dominated possession early but found little room against a compact Union block. Frederik Ronnow kept the hosts level before the interval, first denying Yan Diomande after a strong individual run and then reacting sharply to keep out Christoph Baumgartner's header from a corner. Union offered limited attacking threat but remained organized, almost taking the lead when Janik Haberer headed narrowly wide in stoppage time.

The match turned shortly before the hour mark. After Union won the ball high up the pitch, Jeong Woo-yeong slipped a precise pass into Oliver Burke, who curled a superb left-footed finish into the top corner to give the hosts the lead.

Leipzig responded within three minutes as substitute Tidiam Gomis made an immediate impact, taking a touch inside the area before drilling a powerful shot past Ronnow to level the contest. Union, however, answered quickly. Another substitute, Christopher Trimmel, delivered a pinpoint cross from the right, and Ilyas Ansah rose highest to head home from close range.

Leipzig pushed for another equalizer but struggled for ideas against Union's deep defensive block. The hosts remained dangerous on the counter and sealed the result in stoppage time as Tim Skarke finished calmly after a swift break involving Andras Schafer and Andrej Ilic.

"It was a good overall performance," said Union captain Christopher Trimmel. "Leipzig were better in the first half and had chances, but it feels very good to put in a game like this."

Leipzig coach Ole Werner admitted frustration. "I'm disappointed with the result and our performance. It was an intense battle, but Union handled the decisive moments better and we lost our composure," he said.

The win lifts Union to eighth place on 18 points from 14 matches, while Leipzig remains second on 29, eight behind leader Bayern Munich and one ahead of Borussia Dortmund.