WTA FINALS Impressive Simona Halep loses only three games against Flavia Pennetta

But the No.3-seeded Sharapova never stopped fighting, saving all those break points and building a 5-2 lead, and after Radwanska closed the gap to 5-4, the Russian finally closed it out, 4-6, 6-3, 6-4.

Pennetta will first face world number two Halep while Sharapova takes on Radwanska, over whom she has an impressive 12-2 record. “Here I was well prepared, and I knew how to play against her”.

Sharapova won the WTA Finals trophy on her tournament debut in 2004, and was a finalist two more times. “I played my best in the first set, fast, smart and aggressive”, Halep said in her on-court interview.

“I was expecting that she’s going to play the same like in (New York), and I knew how to adapt the game”.

Maria Sharapova hasn’t played a whole match since Wimbledon but the Russian believes she’s healthy enough to compete Sunday at the season-ending WTA Finals.

After the withdrawal of World No. 1 tennis player Serena Williams, second ranked Romanian Simona Halep becomes the top seed at the BNP Paribas WTA Finals held in Singapore.

Although Sharapova has still had a very successful season – winning Brisbane and Rome, finishing runner-up to Serena Williams at the Australian Open and making the Wimbledon semifinals – she has often struggled for full fitness, most recently with a right leg injury which saw Sharapova miss the entire US Open Series and, after an aborted comeback attempt in Wuhan, the Asian swing.

She reckons: “Considering I haven’t played much, it doesn’t change much for me”.

Sharapova’s appearance in Singapore was cemented by her consistent performance during the first half of the season.

“This is my first completed match since July, so it’s a pretty big deal for me”, Sharapova told the WTA website. “I was really happy to be back here”.

He added: “Maybe she wants to go after that Slam again and see if she can do it. But it will be great to have her back in ’16, and we hope she’s coming back as energized and excited as she says she’s going to be”.

With 21-time Grand Slam-winner Serena Williams opting to rest, the tournament has been thrown wide open with injuries especially likely to be the wildcard in Singapore.

“I would love to play a little bit better, but I still have my chance”.

The opening matches in the white group take place on Monday, with second seed Garbine Muguruza facing Lucie Safarova and Petra Kvitova taking on Angelique Kerber. She cited both as factors in her withdrawal announcement, which came more than three weeks before the Finals.