Moonballs from qualifier doom Wimbledon champ

Instead of trying to match Wimbledon champion Petra Kvitova's power, unknown Aleksandra Krunic confounded her with looping shots and frustrated her by chasing down every ball.

When it was all over, after the last of Kvitova's 34 unforced errors sailed wide, Krunic crumpled to the ground in disbelief at what she had just done - a qualifier ranked 145th, she toppled the No 3 seed 6-4, 6-4, the latest departure by a top woman in the US Open's first week.

"Of course, I didn't expect to win," said Krunic, a 21-year-old Serb who until this tournament had not even taken a set from a player in the top 30.