INDIAN WELLS  - World number one Victoria Azarenka survived an opening-match scare to beat Mona Barthel 6-4, 6-7 (4/7), 7-6 (8/6) in a three-hour marathon at the Indian Wells tournament Friday.

The 22-year-old Azarenka appeared headed for disaster, trailing 4-1 in the third set but the unseeded German Barthel could not close the deal.

"It was a survival," Azarenka said. "She had nothing to lose and I wanted to go for my shots but I hesitated. "Today my game was not at its best but the most important thing is I won."

Azarenka arrived in Indian Wells riding a 17-0 match win streak which has taken her to the final of her last five tournaments, but the Barthel made her work to extend her winning run.

It was the third time Azarenka and Barthel have locked horns this season, with the top ranked player beating Barthel 6-2, 6-4 en route to the Australian Open title in January and again 6-1, 6-0 last month in Doha. "Mona was real motivated to beat me. She played great," Azarenka said.

Azarenka clinched victory on her second match point of the tie-breaker after coming back from the brink in the third set.

Earlier in the tie-breaker Azarenka allowed Barthel to level it at 4-4 when the top seed delivered her 12th double fault of the match. The win means Azarenka, who claimed her first Grand Slam title in Melbourne, will face Svetlana Kuznetsova in the third round, who advanced after Swiss Timea Bacsinszky pulled out of their match with a wrist injury.

Azarenka, who withdrew from the WTA event in Dubai last month with an ankle injury, won despite struggling on her serve.

She pulled out of Indian Wells last year with an injury in the middle of her quarter-final match against Caroline Wozniacki.

The dogged Barthel, ranked 37th in the world, had her finest moments in the second set and served for the set in the third. She lost the first set 6-4 then forced a tiebreaker after being down 5-1 in the second.

Despite defeat the 21-year-old said she could eventually beat Azarenka. "It was difficult serving for the match against the world number one," Barthel said. "I am sad I couldn't win, but I will get another chance."

Barthel possesses an aggressive return game, potent backhand and moves quickly around the court for a 1.85 metre (6ft 1in) tall player. She also stepped up her play with precision groundstrokes on the longer rallies at key stages in the match.

"This year I have improved a lot. I am just trying to get used to the tour. Everything is new for me. I just want to see where I am at the end of the year," Barthel said. Former Indian Wells winner Jelena Jankovic became the first seed to crash out Friday, losing in straight sets 6-4, 6-3 to world No. 99 Jamie Hampton.

The 12th seeded Jankovic blamed her second round loss on fatigue, specifically the jet lag from flying all the way from southeast Asia and then arriving in the California desert on Monday night.

"Today I was a shadow of myself," Jankovic said. "I didn't feel like I did anything right."

Reigning French Open champion Li Na came from behind to take her opening second-round match against Galina Voskoboeva 3-6, 6-3, 6-3.

Li, who is the first Asian player to win a Grand Slam title, had two aces and won 67 percent of her first serve points.

She advances to the third round where she will face countrywoman Zheng Jie who beat Michaella Krajicek 6-1, 6-3 earlier on Friday.

Jankovic wasn't only former champion to be eliminated as two-time winner Daniela Hantuchova lost in three sets 6-3, 6-7 (7/9), 6-3 to Klara Zakopalova. Hantuchova won Indian Wells in 2002 and 2007.

In other second round WTA matches, third seeded Petra Kvitova easily beat fellow Czech Barbora Zahlavova Strycova 6-1, 6-3 in the night match, ninth seeded Vera Zvonareva of Russia beat Kimiko Date-Krumm of Japan 6-3, 6-4 and fifth seed Agnieszka Radwanska cruised past Sorana Cirstea 6-2, 6-4.

On the men's ATP side, Germany's Tommy Haas won his first round match over Jarkko Nieminen of Finland 7-6 (11/9), 6-4 and Marcos Baghdatis beat Jeremy Chardy of France 6-3, 6-4.

Argentine David Nalbandian beat Polito Starace of Italy 7-6 (7/4), 6-0 and France's Michael Llodra defeated Latvian Ernests Gulbis 6-3, 5-7, 7-6 (7/3).