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 semi-finalist here in 2008, told reporters. "I just tried to fight for every point and kept going and kept going.
"I couldn't really play consistently the whole time. I would play a couple of points well and then I would just give away a lot of points. I would give, in a way, a lot of gifts."
Errani had been bidding to beat a top-10 player for the first time in 12 attempts and she broke the world number nine three times to sweep through the opening set in just 31 minutes.
Jankovic squandered a 3-1 lead in the second, along with five set points in the tiebreak, but levelled the match with a crunching forehand winner down the line.
The final set was also an up-and-down affair with Errani being broken three times and Jankovic twice but the Serb made her greater experience count.
After trailing 2-4, she won the next four games to reach the fourth round for the third time in four years.
Jankovic will next meet 17th-seeded Israeli Shahar Peer, who beat ninth seed Flavia Pennetta of Italy 6-4 6-7 6-1.
Clijsters, who returned to competition in 2009 following a two-year retirement and won her second U.S. Open title in just her third tournament back, 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 into a 4-0 lead in the third-set tiebreak before losing momentum.
After the 23rd-seeded Russian had clawed her way back to 4-4, Clijsters netted a backhand, struck a forehand wide and then dumped a forehand into the net to lose the match.
Earlier, holder Vera Zvonareva of Russia comfortably advanced by beating Latvia's Anastasija Sevastova 6-2 6-3 and eighth-seeded Australian Samantha Stosur crushed Anastasia Pavlyuchenkova of Russia 6-3 6-0.