NEW YORK, Sept 1 (Reuters) - Spain's Carla Suarez Navarro became the first player to reach the quarter-finals at the U.S. Open when she upset Germany's Angelique Kerber on Sunday.
After losing the opening set, Suarez Navarro clawed her way back to win 4-6 6-3 7-6(3) after failing to serve out the match at her first chance.
"It was so difficult, Angelique was fighting all the time," said Suarez Navarro, seeded 18th. "I was so nervous."
Suarez Navarro's quarter-final opponent is Serena Williams, who booked her place in the last eight a few minutes after the Spaniard when she completed a 6-4 6-1 win over Sloane Stephens. (Reporting by Julian Linden; editing by Gene Cherry)