Haas Czechs out, then Czechs in
Germany's Tommy Haas serves the ball to Czech Republic's Radek Stepanek during their quarter finals match as part of the Vienna ATP 250 tennis tournament held in Vienna on October 18, 2013
Second-seeded Haas, the 2001 champion in Vienna, spent one and three-quarter hours in holding off fifth seed Radek Stepanek, a member of his nation's 2012 Davis Cup championship side, 7-6 (12/10), 6-3.
The 35-year-old Haas will Saturday take on eighth-seeded Czech Lukas Rosol, who beat Belgian Ruben Bemelmans 6-3, 1-6, 6-3 in his quarter-final.
At the top of the draw, Robin Haase of the Netherlands recovered to beat third seed Fabio Fognini 6-7 (4/7), 6-1, 6-1 as the colourful Italian faded away after winning a tight opening set.
Top-seeded 2011 champion Jo-Wilfried Tsonga was facing young Austrian hope Dominic Thiem later Friday.
Haas, chasing a place in the eight-man season ATP World Tour Finals in London next month, stayed in touch on provisional 12th as he booked his place in the final four.
The one-time world number two won the 63-minute opening set against Stepanek only after saving four set points and converting on his own second chance.
With the opening set in the bag, Haas then got to work to finish off the job against his 34-year-old opponent, breaking for 4-2 in the second set and advancing on his first match point.
"The tiebreak was very important, it was tough. Saving those set points was important, it helped me make the momentum swing for the second set," said Haas, how has beaten Stepanek in four of seven meetings.
Haas has never faced Rosol, who famously knocked Rafael Nadal out of Wimbledon in 2012.