Former runner-up Tommy Haas was a quarterfinal upset loser Friday at the hands of Italian Fabio Fognini at the $530,000 Mercedes Cup tennis event.
The top-seeded, long-time German crowd favorite Haas succumbed to the fifth-seeded Fognini 6-2, 6-4 in 74 minutes on the red clay at Weissenhof Tennis Club. Fognini broke Haas' serve three times while holding his serve throughout on Day 5.
The 35-year-old world No. 11 Haas was the Stuttgart runner-up back in 1999.
The German faithful were treated to a quarterfinal victory when second-seeded Philipp Kohlschreiber straight-setted 2010 Stuttgart runner-up Gael Monfils, of France, 6-4, 6-4.
Another upset came when 2009 Stuttgart runner-up Victor Hanescu, of Romania, took out fourth-seeded Frenchman Benoit Paire 7-5, 6-2. Hanescu will tangle with Kohlschreiber in Saturday's semifinals.
The other semi will pit Fognini against rising Spaniard Roberto Bautista Agut, who was leading Michael Berrer 6-2, 0-1 when the German wild card retired with a left elbow injury on Day 5.
This week's champion will take home $110,000 and a brand new Mercedes-Benz sports car.