LUXEMBOURG: US Open champion Kim Clijsters suffered a midnight defeat at the 220,000-dollar WTA Luxembourg tournament when Swiss veteran Patty Schnyder won their second round clash 6-4, 3-6, 7-6 (8/6).

Clijsters, the second seed, was bidding for a sixth title in this event, and second tournament victory since her return from two years of retirement.

Schnyder, the world number 47, had beaten Clijsters just twice in their eight prior meetings, and one of those was because of an injury retirement.

But she battled for almost two hours, recovering from a lost 5-3 lead in the third set and then regrouping after letting go a 4-0 lead in the tie-break.

"Patty played extremely smart. It's tough to force errors on her and break through her game," said Clijsters.

"I made more unforced errors and my first serve wasn't working the way I would have liked it to. I had my chances in the first set and I tried to fight through. It's disappointing when you're not playing your best."

Schnyder goes on to face German sixth seed Sabine Lisicki in the quarter-finals.