Fábio Silva and Konstantinos Karetsas scored for the German side, while Aitor Ruibal found the net for Betis in an entertaining Matchday 4 encounter at Signal Iduna Park.
The first half ended goalless, with both teams creating opportunities but struggling to find the breakthrough. Betis threatened through Antony, whose effort was ruled out for offside in the 14th minute, while Dortmund also looked dangerous going forward.
Dortmund made the perfect start to the second half when Fábio Silva opened the scoring in the 49th minute. The Portuguese forward reacted quickest after Jobe Bellingham's effort was saved by goalkeeper Álvaro Valles, turning the rebound into the net from close range.
However, Betis responded in the 67th minute. Abde Ezzalzouli provided the assist for Aitor Ruibal, who finished from inside the penalty area to restore parity and put the visitors back in contention.
Dortmund refused to settle for a draw and regained the lead five minutes later. Fábio Silva turned provider, setting up Konstantinos Karetsas, who calmly finished with his left foot to make it 2-1.
The hosts defended their advantage during the closing stages, despite Betis attempting to find another equaliser. Dortmund held firm to secure their third victory in the Champions League league phase.
Dortmund maintain Champions League momentum
The victory strengthened Dortmund's campaign in Europe, giving them nine points from their opening four league-phase matches.
It was also an important response after their 2-2 draw against Bayern Munich in the Bundesliga at the weekend.
However, Dortmund will be concerned about the fitness of Serhou Guirassy, who was forced off with an injury in the first half and replaced by Karetsas.
Match details
• Borussia Dortmund: 2
• Real Betis: 1
• Dortmund scorers: Fábio Silva 49', Konstantinos Karetsas 72'.
• Real Betis scorer: Aitor Ruibal 67'.
• Competition: UEFA Champions League, League Phase, Matchday 4.
• Venue: Signal Iduna Park, Dortmund.
• Date: Wednesday, 4 November 2026.