Romania’s Simona Halep kicked off her campaign for a maiden WTA Finals title in emphatic fashion with a 6-0 6-3 victory over US Open champion Flavia Pennetta in the first match of the eight-woman season-ending tournament yesterday.

While the opener proved to be a sprint, the second ‘Red Group’ tie was a marathon when Maria Sharapova beat Agnieszka Radwanska 4-6 6-3 6-4 in a full-blooded encounter marked by several swings in momentum as both players struggled on serve.

World number two Halep is the highest ranked player in the field after Serena Williams, who has won the tournament for the last three years, withdrew citing the need to rest after a year spent carrying injuries in her quest for a calendar Grand Slam.

Halep crushed Williams in round robin play a year ago before losing to the American in the final and her love of the Singapore Indoor Stadium hard court was evident in a first set she wrapped up in 26 minutes after breaking serve three times.

“I feel the same now as I did against Serena,” Halep told reporters. “I can play my best tennis here yet I didn’t play my best today, but I played good tennis.”

Sidelined by leg and arm injuries, Sharapova had yet to complete a match since Wimbledon but after shaking off some initial rust, the Russian was back to her very best against Radwanska, playing each point as if her life depended on it.

“Coming into this event, I tried to do everything I could to be healthy and although I didn’t play my best tennis today, sometimes that’s not what matters,” Sharapova said of a match that lasted two hours, 48 minutes with a large portion of games going to deuce.

“I’m so happy that I got through and have a chance to play two more matches to end the season and hopefully more, so I couldn’t be happier at this point.”

The ‘White Group’ consists of Garbine Muguruza, Petra Kvitova, Angelique Kerber and Lucie Safarova, with play in that pool starting today.