NEW YORK — Wimbledon champion Petra Kvitova was stunned in the third round of the U.S. Open by a scrambling, moon-balling qualifier ranked No. 145.
Aleksandra Krunic, a 21-year-old Serb who until last week had not taken even a set from a player in the top 30, crumpled to the court in celebration and shock Saturday when she pulled off the 6-4, 6-4 upset of the third-seeded Czech.
"Of course, I didn't expect to win," said Krunic, the second qualifier to pull off such a shocker after 121st-ranked Mirjana Lucic-Baroni beat No. 2-seeded Simona Halep on Friday.
Even when Krunic took the lead in the second set and the Louis Armstrong Stadium crowd was cheering her on, "I just told to myself, It's still on her, you still have nothing to lose. I really focused my 100 percent not to think about anything that is happening — about the court, about so many people, about Petra.''
Only three of the top eight women's seeds remain: No. 1 Serena Williams, No. 5 Maria Sharapova and No. 7 Eugenie Bouchard.
Bouchard, the Wimbledon runnerup, pulled out a suddenly tight match late Saturday, edging 30th-seeded Barbora Zahlavova Strycova of the Czech Republic 6-2, 6-7 (2-7), 6-4 to reach the fourth round for the first time.
Kvitova, who would have ascended to the No. 1 ranking if she won the U.S. Open and Williams had lost before the quarterfinal, committed 34 unforced errors against the fast-moving Krunic, who slid and sometimes went into a split to chase down every ball and make her opponent hit one more shot.
Kvitova too often failed to do so, including what should have been an easy putaway of a drop shot that put Krunic a point away from winning the first set. Kvitova sprayed a backhand long on the next point to lose it.
Those problems continued in the second set, and in an epic 27-stroke rally on match point, Krunic looped several towering shots before Kvitova sailed yet another forehand out to end it.
"She played really unbelievable tennis and she put a lot of balls back … almost all of them," said the two-time Wimbledon champ who has never advanced past the fourth round at the U.S. Open. "I was trying to fight and fighting every point, but it was so difficult. It wasn't really my day."
Losing to the same opponent in the third round for the third consecutive year, 13th-seeded John Isner of Tampa was beaten 7-6 (7-4), 4-6, 7-6 (7-2), 7-6 (7-4) by Germany's Philipp Kohlschreiber, leaving zero American men in the field.
Today's key matches
Men: Roger Federer (2) vs. Marcel Granollers, David Ferrer (4) vs. Gilles Simon (26), Tomas Berdych (6) vs. Teymuraz Gabashvili, Grigor Dimitrov (7) vs. David Goffin
Women: Maria Sharapova (5) vs. Caroline Wozniacki (10), Jelena Jankovic (9) vs. Belinda Bencic, Sara Errani (13) vs. Mirjana Lucic-Baroni, Lucie Safarova (14) vs. Peng Shuai
TV: 11 a.m., Ch. 10, CBSSN; 7 p.m., Tennis