February 2010 had been the occasion of Bayern's last league or cup win over Dortmund -- a six-game stretch -- but Robben's thunderbolt two minutes before the break at the Allianz Arena was enough to put Munich in the last four. A pre-season Supercup final win in Munich last August had been Bayern's only source of comfort against Borussia recently. Despite having spent much of this season on Bayern' bench, Robben took over on the left wing from France's Franck Ribery, who was suspended, to show coach Jupp Heynckes what he has been missing. The 29-year-old ex-Chelsea and Real Madrid star sank to his knees and beat the turf at the final whistle in delight. He has now scored in three of Bayern's last four games after netting in recent Bundesliga wins over Wolfsburg and the 6-1 drubbing of Werder Bremen last Saturday. This was the clash of Germany's titans -- Bayern Munich, 17 points clear in the Bundesliga against defending league champions and cup holders Dortmund, who have dominated the top tier of German football for the last two years. Germany defender Mats Hummels dropped out the day of the game with flu and in his place Brazilian Felipe Santana partnered Neven Subotic at centre-back for Dortmund. Robben's inclusion for the suspended Ribery was the only change from the team which won 3-1 at Arsenal in the Champions League just over a week ago. Dortmund hammered Bayern 5-2 in last May's German Cup final, when Poland striker Robert Lewandowski netted a hat-trick. If Wednesday's game needed extra spice, Lewandowski has been strongly linked to a move to Bayern with his contract to expire in 2014. In a tight, nervy cup game, both teams had their opportunities. The brightest chance of the first-half fell to Javi Martinez when his shot straight at Roman Weidenfeller was parried and the Dortmund goalkeeper scrambled back to grab the loose ball on on 36 minutes. Bayern kept up the pressure and when Dortmund's Marcel Schmelzer hit a weak clearance, Robben's shot from 18 metres clocked 115km/h (70mph) as it hit the top-right corner on 43 minutes for what proved to be the winner. With Dortmund out, Bayern are now clear cup favourites and are on course to be the first team to win the treble of German league, cup and Champions League titles in their quest to end their three-year wait for silverware. VfB Stuttgart, who beat third-division VfL Bochum 2-0, Wolfsburg and Freiburg are the other teams to go into the pot for Sunday's draw with the semi-finals to be held on April 16/17, with the final on June 1 in Berlin.