English winger Gittens opened the scoring with a stunning long-range solo effort before half-time, shooting in from the edge of the box.

Bensebaini headed in a Pascal Gross corner early in the second half and Guirassy came off the bench to add a third late, sealing the result.

The win, Dortmund's first away victory in any competition since September, sent them into the top four and all but sealed at least a spot in the knockout rounds.

"We did really well and didn't let many chances in. We were very dominant with the ball -- it was a really good game from us," Dortmund goalkeeper Gregor Kobel told DAZN.

"We're just happy," said defender Nico Schlotterbeck. "We won in Zagreb and we had the whole game under control. Things are going well."

One concern for Dortmund coach Nuri Sahin will be Julian Brandt's fitness ahead of Saturday's game against Bayern Munich.

"I hope it's not too bad. Brandt is extremely important for our game," Sahin said, adding the 28-year-old was "almost irreplaceable".

"It'll be a huge fight," Kobel said of the Bayern clash.

"If we give everything, we can try and get the maximum out of it."

Midfielder Brandt, captaining the side with Emre Can on the bench, was replaced after limping off before half-time with a reported thigh injury.

Zagreb had rebounded in the Champions League after an opening round 9-2 thrashing at the hands of Dortmund's German rivals Bayern, winning two and drawing another to climb into the knockout places.

Dortmund halt away struggles

The home fans welcomed last season's Champions League finalists with loud fireworks in a stadium still showing scars of a 2020 earthquake, with its capacity reduced by 14,000 due to fears of collapse.

The visitors, on a run of six straight away losses in all competitions, took a while to get started, Zagreb's Ronael Pierre-Gabriel blasting just over the bar on the counter and startling Dortmund into life.

Donyell Malen hit the crossbar after 28 minutes. Gittens found Malen unmarked and one-on-one with the goalkeeper in the 41st minute but the Dutchman headed wide.

Seconds later, Gittens took matters into his own hands, dribbling past three defenders to give himself space before unleashing a superb dipping strike into the top right corner.

Still just 20, the goal was Gittens' fourth in his fifth Champions League game this campaign.

Gross found Bensebaini from a corner just after half-time for Dortmund's second, the Algerian standing tall and heading past the Zagreb keeper.

With one eye on Saturday's clash with Bayern, Sahin made three changes with half an hour remaining, including bringing on Guirassy as he returned from illness.

The Guinean showed excellent touch to seal the match with a goal in the final minute, to match Gittens' tally of four in five Champions League games.

Dortmund have now won four of five outings in the Champions League, other than their 5-2 humbling in the Champions League final rematch against Real Madrid in October.