Cilic knocks off Mathieu; Andreev, Wawrinka, Canas advance

GSTAAD, Switzerland -- Unseeded teen Marin Cilic upset defending champion Paul-Henri Mathieu 6-3, 6-4 on Wednesday in the second round of the Swiss Open.

Mathieu, ranked 18th, is likely to drop out of the top 20 after failing to defend the points he won a year ago.

Cilic defeated the 26-year-old Mathieu for the third straight match, but the first time on clay.

In the quarterfinals, the 43rd-ranked Cilic will face seventh-seeded Igor Andreev of Russia, who beat Florent Serra of France 7-5, 6-4.

Top-seeded Stanislas Wawrinka of Switzerland struggled to get past his Davis Cup teammate Stephane Bohli 7-6 (6), 5-7, 7-6 (3).

He will play Guillermo Canas of Argentina in the quarterfinals Friday. The eighth-seeded Canas advanced when Kristof Vliegen of Belgium withdrew.