Achraf Hakimi scored twice as Borussia Dortmund came from 2-0 down to beat Inter 3-2 and give themselves a major boost in the Champions League.
Lautaro Martinez and Matias Vecino had put the visitors in the driving seat at Signal Iduna Park, two weeks on from their 2-0 defeat of Lucien Favre's side in Milan.
Dortmund came roaring back in the second half, though, with Achraf netting his double either side of a Julian Brandt strike to secure what could prove to be a valuable victory.
Martinez became the first Inter player to score in three consecutive Champions League appearances since Samuel Eto'o in 2010 when he raced down the right, cut back into the box past the covering defence and side-footed high beyond Roman Burki.
It was a deserved lead for the visitors, who were keeping Dortmund restricted to half-chances, with Mario Gotze denied by Samir Handanovic from the best of their early openings.
After 40 minutes it was 2-0 thanks to a flowing counter-attack. Marcelo Brozovic showed great footwork, Martinez turned and spread the ball out to Antonio Candreva, and his cut-back was swept into the net by the arriving Vecino.
Dortmund started the second half brightly and got a goal back when Achraf scuffed the ball into the left-hand corner after being teed up by Gotze.
Pressure was building on Inter and they gifted Dortmund their equaliser 13 minutes later, making a mess of a throw-in near their own box to allow Brandt to steal in and slot past Handanovic.
The comeback was completed 13 minutes from time, when Achraf raced into the box from the right wing to dispatch Jadon Sancho's pass beneath Handanovic.
What does it mean? Barcelona and Dortmund in pole position to progress
Barcelona, who were held by Slavia Prague earlier at Camp Nou, remain top of Group F and four points clear of Dortmund.
Antonio Conte's side will hope for a favour from Barca against Dortmund on matchday five to increase their chances of going through.
Achraf provides surprise killer touch
Dortmund have lacked a cutting edge in recent weeks, but Achraf showed his attacking team-mates how it should be done with two crucial goals, his second a particularly precise finish.
Conte cannot react in time
The drop-off in Inter's second-half performance was peculiar and Conte seemed unable to arrest it with substitutions or tactical changes. Champions League success remains hard to come by for him.
Dortmund head to Bayern Munich in the Bundesliga on Saturday, while Inter host Hellas Verona in Serie A.