GSTAAD, Switzerland - A day after Roger Federer lost at the Swiss Open citing back pains as a problem, local favourite Stanislas Wawrinka retired from his quarterfinal match Friday with the same injury.
The second-seeded Wawrinka was unable to continue after a medical timeout more than two hours into his match with Feliciano Lopez, who was leading 6-4, 2-6, 4-3 at the time.
Wawrinka, ranked No. 10, extended an unhappy run at his home tournament. He has won only five matches — all against players outside the top 50 — in seven visits since reaching the 2005 final.
The fifth-seeded Lopez will face Robin Haase of the Netherlands in the clay-court tournament on Saturday.
The 57th-ranked Haase beat 2011 champion Marcel Granollers of Spain 5-7, 6-3, 7-6 (5) in 2 hours, 30 minutes.
Federer's conqueror, Daniel Brands of Germany, failed to build to build on that success in losing 6-3, 6-4 to Victor Hanescu.
Hanescu, the 2008 Gstaad champion, forced one service break in each set to ease to victory.
Mikhail Youzhny will next face Hanescu after beating fourth-seeded Juan Monaco of Argentina 5-7, 6-4, 7-6 (7).
The sixth-seeded Russian saved three match points in the deciding tiebreaker.