Niko Kovac has urged his Borussia Dortmund side to be "aggressive" after their defeat to Tottenham in the Champions League.

Dortmund lost 2-0 to Spurs on Tuesday, with Kovac's side on the back foot for the majority of the match in north London.

They are 11 points behind Bayern Munich at the Bundesliga summit, despite losing just once in the league this term, with many criticising second-place Dortmund.

Ahead of their trip to Union Berlin, Kovac admitted there is room for improvement at Dortmund, but insisted that they have progressed from last season.

"Of course, I know that we have a few things to improve on, but I also know that the team has improved significantly compared to last season," said Kovac when reflecting on the defeat to Spurs.

"[Last season] it wasn’t the playing style that was criticised but the results. I’m not happy with certain situations either. If you win only 36% of the duels in the first half, then it’s difficult to win the game.

"For me, football is first and foremost about intensity and being aggressive. Tackling is the essence of football."

Union Berlin are ninth in the German top-flight and five points off the European places after stringing together a five-match unbeaten run.

However, they have drawn all three of their games in 2026, most recently sharing the points with Stuttgart (1-1).

PLAYERS TO WATCH

Union Berlin – Jeong Woo-yeong

Jeong Woo-yeong has been in impressive form for Union either side of the winter break.

The midfielder has directly contributed to three goals (two goals, one assist) in his last five Bundesliga matches, after failing to register a direct involvement in his first 11 games this season.

Borussia Dortmund – Emre Can

Emre Can has netted all 11 of his penalties in the Bundesliga. Only Harry Kane (20), Hans-Joachim Abel (16), Ludwig Nolden (15) and Otto Rehagel (12) have taken more while maintaining a 100% record in the German top-flight.

Opponents Union have already conceded three penalty goals in the 2025-26 Bundesliga season, with only Stuttgart (five) conceding more across the league.

MATCH PREDICTION – BORUSSIA DORTMUND WIN

With 39 points from 18 games, Dortmund are enjoying their best Bundesliga season in seven years – in 2018-19 under Lucien Favre they had 45 points at this stage.

Union have lost five of their last six top-flight matches against Dortmund (W1).

However, Dortmund have lost four of their six Bundesliga away games at the Stadion An der Alten Forsterei – they do not have a higher loss rate against any team they have played at least five times away in the Bundesliga than against Union (67%).

Berlin have gained points from losing positions in all three of their Bundesliga matches in 2026 (D3), having failed to earn a single point when falling behind in their 15 league games before the winter break.

Dortmund, meanwhile, have dropped 10 points from winning positions in the Bundesliga this season, with eight of these coming away from home.

OPTA WIN PROBABILITY

Union Berlin – 28.7%

Draw – 26.2%

Borussia Dortmund – 45.2%