Japanese attacking midfielder Shinji Kagawa opened the scoring after 11 minutes when he eluded his challenger on the edge of the area and sent a low shot into the bottom corner.

Paraguay striker Lucas Barrios doubled Dortmund's lead in the 72nd minute with a close-range shot despite being under pressure from two defenders.

Hanover's hopes of getting something from the game were dealt a blow five minutes later when Tunisian defender Karim Haggui was sent off.

Dortmund made the most of their numerical advantage by scoring two late goals through substitutes Robert Lewandowski and Jakub Blaszczykowski.

"We deserved this win today but maybe the score is a bit flattering," Dortmund coach Jurgen Klopp said after the game.

"Our second goal was the turning point and I think Hanover lost confidence after that."

Dortmund are still missing Egyptian striker Mohamed Zidan, who is nursing a serious knee injury he picked up last April. He is expected to return to action later this month.

Klopp's side, who last won the Bundesliga in 2002, have 28 points from 11 games, four ahead of second-placed Mainz who slumped to a 1-0 defeat at Freiburg on Saturday.