Indian Wells: Li Na downs Dominika Cibulkova to reach semifinals; Flavia Pennetta beats Sloane Stephens

Australian Open champion Li Na booked her semi-final berth at the Indian Wells hardcourt tennis tournament with a 6-3, 4-6, 6-3 win over Dominika Cibulkova.

China's Li, the world number two who is the top seed in the event, reprised her triumph over Slovakia's Cibulkova in the final in Melbourne, although she labored two hours and 36 minutes to do it.

Li was firmly in control in the opening set, breaking Cibulkova to start the match.

She dropped her own serve in the next game, but immediately broke the Slovakian again, and fended off two break points in the fourth game to stretch her advantage.

Li couldn't convert break chances in the fifth, but pocketed the set with a break in the ninth game, sealing it with a forehand cross court winner.

But Cibulkova turned the tables in the second set as Li's error count crept up, breaking the Chinese in the third and fifth games and holding for a 5-1 lead.

Li won the next three games, but couldn't hold off Cibulkova any longer as the Slovakian held to force a third set.

After an exchange of breaks in the first two games, Li gained the decisive break in the eighth.

Both players struggled with their serves at times on the sunny stadium court, each coughing up eight double faults and facing double-digit break points.

Li, who successfully defended her title in Shenzhen before capturing her second career Grand Slam title in Australia, will face Italian veteran Flavia Pennetta in the semi-finals.

Pennetta, 32, held off 20-year-old American Sloane Stephens 6-4, 5-7, 6-4.

Pennetta took the first set against an error-prone Stephens with a single break of serve.

Both players were erratic in the second, but Pennetta was within two points of winning the match when she served at 5-4, only lose six games in a row to drop the second set and fall 3-0 down in the third.

All the while, gusting winds were picking up, raising a desert dust storm west of the stadium.

Pennetta managed to keep her focus and break Stephens twice to secure the 48th semi-final of her career and her first since last year's US Open.

"We didn't have a lot of fun today," Pennetta said. "We didn't play our best tennis.

"Maybe in the beginning we played much better, and in the second set one, but the third was a disaster for both of us.

"Outside it's crazy now. It's coming the wind from nowhere."

The other women's semi-final between second-seeded Agnieszka Radwanska and Romanian Simona Halep was set on Wednesday.

Radwanska reached the semi-finals of the Australian Open, where she lost to Cibulkova. She has won three of five career meetings with Halep, but the 22-year-old Romanian scored an impressive victory in their last encounter, in the semi-finals en route to the title in Doha last month.