Jelena Jankovic had to fight her way into the fourth round of the Indian Wells WTA tournament on Monday while former world number one Kim Clijsters was upset by Russian Alisa Kleybanova.
Serbian sixth seed Jankovic beat Italian Sara Errani 2-6 7-6 6-4 in an error-strewn marathon on the stadium court before twice champion Clijsters of Belgium tumbled out 6-4 1-6 7-6.
Third seed Victoria Azarenka of Belarus also made a premature exit, going down 7-6 6-2 at the hands of 28th-seeded Maria Jose Martinez Sanchez of Spain.
Jankovic piled up 57 unforced errors, compared to Errani's 42, to clinch victory in two hours, 48 minutes when the Italian made a hash of an overhead smash after a protracted rally.
"It was really a battle out there, and I just tried to stay positive as much as I could," Jankovic, a semifinalist here in 2008, told reporters. "I just tried to fight for every point and kept going and kept going."
Jankovic will next meet 17th-seeded Israeli Shahar Peer, who beat ninth seed Flavia Pennetta of Italy 6-4 6-7 6-1.
Clijsters appeared to regain control after losing a tight opening set to Kleybanova. The 26-year-old Belgian broke her opponent four times to storm through the second set and raced to a 4-0 lead in the third-set tie-break before losing momentum.