Borussia Dortmund snatched a 1-0 victory over Chelsea in the Champions League round of 16 first leg on Wednesday courtesy of Karim Adeyemi's superb goal to extend their winning run this year.
Germany international Adeyemi sprinted more than 60 metres and slotted home against the run of play to give his team the advantage going into the return leg in London on March 7.
Big-spending Chelsea's inefficiency in front of goal has been an issue for the Premier League club this season and they have registered only one win in 2023.
They missed a number of good chances against Dortmund, including hitting the woodwork through Joao Felix, but failed to find an equaliser.
They looked sharper at the start of the game and Thiago Silva put the ball in the net after 16 minutes, but the Chelsea captain was penalised for a handball after he had tried to head in a cross.
Dortmund gradually found more space and hit the side netting through Sebastien Haller in the 27th minute.
The visitors, who spent more than $350 million on transfers during the winter window to bring in eight players, responded with two big chances of their own to Felix, with the Portuguese also hitting the crossbar after beating Kobel.
Both teams had to wait until the second half to get their first shots on target, with Kobel punching a powerful Reece James free kick wide and his Chelsea counterpart, Kepa Arrizabalaga, stopping Julian Brandt's low drive.
But with Chelsea pushing for a goal and forcing another fine Kobel save, it was Dortmund who struck after 63 minutes.
Adeyemi picked up a clearance from a Chelsea corner and raced half the length of the pitch before beating Fernandez in the sprint and rounding Kepa to score.
The hosts had to survive late scares, with Kalidou Koulibaly's shot cleared off the line by Emre Can and Kobel again denying Fernandez deep in stoppage time with a great save before the German side secured their seventh consecutive win.