INDIAN WELLS, UNITED STATES (AFP) - Simona Halep claimed the biggest title of her career on Sunday, lifting the Indian Wells WTA trophy with a 2-6, 7-5, 6-4 victory over former champion Jelena Jankovic.

The hard-fought triumph over the former world No. 1 from Serbia made Romania's 23-year-old Halep the first player to win three WTA titles this year. Halep, ranked third in the world, won four of the final five games in the third set to earn the marathon victory in 2hr 37min.

"I don't know how I won today because I didn't play my best," Halep said. "But I just wanted to fight till the end. Every match was very important for me, for my mind. I just had the confidence that I had a chance here in this tournament, and I just did everything to get it. I'm really happy that I have another title."

Halep and Jankovic have a history of playing long, tight matches and Sunday was no different. They have now gone to three sets in all five career meetings with Halep leading the series 4-1.

Jankovic, who served for the match at 5-4 in the second set but couldn't close it out, was gracious in defeat.

"My opponent Simona was unbelievable," said Jankovic, who turned 30 last month. "She was running like two dogs, left and right for about three hours and at the end I just couldn't keep up anymore. She is the younger one and she was too good at the end."

Halep advanced to the semi-final on a walkover after Serena Williams cut short her long-awaited Indian Wells return because of a knee injury. Halep has shot up the world rankings in the past few years, going from No. 64 in May 2013 to her current No. 3.

She started the 2015 season with her ninth career title by winning the Shenzhen, China tournament. She followed that with a victory in Dubai and also reached the quarter-finals at the Australian Open in January.