Bundesliga leaders Borussia Dortmund stunned by Hannover

Bundesliga leaders Borussia Dortmund crashed to a 4-2 defeat at Hanover on Saturday, collapsing at the back after the sending-off of teenage defender Dan-Axel Zagadou.

Togo striker Ihlas Bebou scored twice for the hosts as Dortmund were picked off on the counter-attack, slumping to a loss that is the last thing coach Peter Bosz needed before Wednesday's Champions League home match against APOEL.

Dortmund are winless in their last three Bundesliga games and will be knocked off the top later with their two nearest rivals, Bayern Munich and RB Leipzig, meeting each other at the Allianz Arena.

Bayern go into that game behind Dortmund on goal difference, with Leipzig a point back in third.

Former Ajax coach Bosz has been criticised for using a 4-1-4-1 system that leaves his side vulnerable against counter-attacks, but he found explanations elsewhere.

"It's got nothing to do with the system, it was because Hanover defended high up the field, not Dortmund," he told Sky.

"There is always space in football, but we lost because Hanover were more aggressive than us and we didn't manage to create goal chances."

Dortmund's star striker Pierre-Emerick Aubameyang had another quiet game as Hanover became the latest team to expose a frail defence that has now conceded nine times in three league games.

Hanover took the lead on 20 minutes when Brazilian striker Jonathas converted a penalty.

Replays showed Dortmund goalkeeper Roman Burki stood his ground and Felix Klaus charged into him, but the penalty stood despite a review from the video assistant referee.

Dortmund equalised seven minutes later when an awful clearance by Hanover's Marvin Bakalorz carried only as far as Zagadou, who smashed home.

However, they were caught on the break as Hanover regained the lead five minutes before the break. Klaus released Jonathas, whose final pass found Bebou to fire home.

Dortmund levelled for a second time when Senegal defender Salif Sane's headed clearance this time found Andrey Yarmolenko, who finished.

Nevertheless, the game swung away from Dortmund when Zagadou, 18, was sent off on the hour after bringing down Jonathas, who was through on goal.

Klaus rifled home the resulting free-kick for Hanover's third goal on the hour mark and Bebou's second of the game secured the points late on as the newly-promoted side climbed to fourth.

"That's a setback for us, we were leading the league and we have to talk about what isn't working", admitted captain Marcel Schmelzer with Dortmund having now thrown away a five-point lead.