Vedad Ibisevic scored the winner in the 63rd minute but Dortmund kept their 12-point lead intact with Bayern Leverkusen, in second place on 49, in action on Sunday at Mainz 05.

Bayern, who agreed earlier this week to part ways with coach Louis van Gaal at the end of the season after three straight defeats in all competitions, climbed to fourth on 45 points, two behind Hanover 96, who lost 4-0 to Cologne on Friday.

Hamburg, whose coach Armin Veh is also leaving at the end of the season, dropped to eighth on 37. Champions Bayern were in control from the start but had to wait until the 40th minute to take the lead when Robben fired in a Franck Ribery pass.

The Dutchman, who had missed the first half of the season through injury, then curled in a free kick seconds after the restart and tapped in his eighth league goal of the season from another Ribery pass on 55 minutes.

The Frenchman turned scorer a little later adding Bayern's fourth with a lovely chip over keeper Frank Rost and forcing Heiko Westermann to tap in an own goal following a solo effort minutes after Thomas Mueller had made it 5-0 on 79 minutes.

Eintracht Frankfurt scored their first goal since the winter break but still lost to 2-1 to Schalke 04, who three days ago advanced to the Champions League quarterfinals.

New signing Angelos Charisteas scored the winner in the 84th minute, seconds after coming on, to lift Schalke to 33 points in 10th place.

Nuremberg snatched a last-gasp win at VfL Wolfsburg with Per Nilsson scoring the winner in stoppage time to move them up to sixth on 42 points, while Kaiserslautern's Erwin Hoffer scored at the death to give his side a vital 2-1 win over Freiburg.