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.
"I think this was also partly a reaction to last week's defeat to Hanover," Van Gaal told reporters.
"Obviously such reactions have to be accompanied by the proper result and today we got that result.
"It is also very good preparation ahead of our match against Inter Milan," said Van Gaal, whose team take a 1-0 lead into the second leg of the Champions League last 16 tie at home against the holders on Tuesday.
Hamburg, whose coach Armin Veh is also leaving at the end of the season, dropped to eighth on 37.
Champions Bayern were in command from the start and hit the woodwork three times before Robben fired in a Franck Ribery pass on 40 minutes.
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 Muller had made it 5-0 on 79 minutes.
Veh said the defeat would not speed up his departure, after opting this week not to stay on one more season.
"I am certainly not going to step down," Veh told reporters.
Dortmund showed none of their usual attacking prowess against Hoffenheim, despite having top striker Lucas Barrios fit to play.
Ibisevic, who had already come close on two occasions, scored just after the hour to hand Dortmund only their third defeat this season.
"Our attitude was good and that is why I am not worried at all with our first loss in the league this year," said Dortmund coach Jurgen Klopp.
Eintracht Frankfurt scored their first goal since the winter break - a 70-metre clearance by Georgios Tzavellas that surpised keeper Manuel Neuer - but still lost 2-1 to Schalke 04, who three days ago advanced to the Champions League quarter-finals.
New signing Angelos Charisteas notched the winner six minutes from time, seconds after coming on, to lift Schalke to 33 points in 10th place.
Nuremberg and Kaiserslautern snatched last-gasp wins over VfL Wolfsburg and Freiburg respectively while last-placed Borussia Moenchengladbach's defender Dante gave them a valuable point with a stoppage-time goal to draw 1-1 at Werder Bremen.
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