Barcelona dominated much of a goalless first half, and were presented with a brilliant chance to open the scoring on the quarter-hour mark. An exceptional outside-of-the-boot cross from Lamine Yamal set up Raphinha, but he dragged the shot wide.
Apart from a skied Marcel Sabitzer shot, Dortmund rarely threatened, and they had Gregor Kobel to thank for their first-half clean sheet. The Swiss goalkeeper had to make two strong saves, firstly denying Yamal’s effort from the edge of the box, before thwarting Jules Koundé with a brilliant stop.
The two teams came flying out for the second half as it began in a frantic, end-to-end manner. First, Dortmund had the ball in the back of the net five minutes in, after Jamie Gittens broke through the Barça backline and squared for Serhou Guirassy to tap in, although that goal was ruled out for offside.
That would cost the hosts, as the Blaugrana went up the other end and Raphinha buried a finish after being slipped in by Dani Olmo.
But Guirassy was becoming more menacing by the minute, and got the opportunity to draw his side level on the hour mark after he was dragged down in the box by the inexperienced Pau Cubarsi. The Guinean striker made no mistake, burying his spot kick and provoking Flick into making a triple change.
Two of the new faces combined to restore Barca’s lead, as Fermín López produced a drilled shot from the edge of the box, which Kobel saved, but Ferran Torres was on hand to turn in the rebound for a third goal in as many games.
Guirassy should have equalised right from kick-off, but somehow headed over from point-blank range. He made amends moments later though, after Iñaki Peña needlessly rushed out of his box, which allowed Pascal Groß to pick out Guirassy to slide the ball home.
Dortmund pushed to find the winning goal, but in doing so, left themselves open at the back. Barça duly punished their hosts on the counterattack as Yamal picked out Torres, whose drilled finish sealed a vital UCL three points for Flick’s men.
The win puts the Catalans in second place, while Dortmund drop to ninth – a point behind eighth-place LOSC Lille.