EASTBOURNE, England — Serena Williams recovered from a slow start to win her first match after being sidelined for nearly a year, defeating Tsvetana Pironkova 1-6, 6-3, 6-4 Tuesday in the first round at Eastbourne.

The 13-time Grand Slam champion initially looked nothing like the player who lifted the 2010 Wimbledon trophy in her last tournament. Her movement was uncertain, and she appeared not to trust her groundstrokes or her usually dominant serve.

"I'm just so happy to be back," said Williams, who hasn't played since Wimbledon because of a foot injury and blood clots on her lungs.

She held for the first time at 5-0 down, with the help of her first ace of the match.

Williams steadied herself and reeled off the first three games of the second set to take control. Despite squandering a 2-0 lead in the decider, she broke again to secure the win and set up a possible second-round match with top-seeded Vera Zvonareva.

However, it looked like a short-lived return when Williams dropped the first set in 27 minutes.

The 29-year-old American walked out to the song "I'm The World's Greatest," chosen by organizers rather than herself. She was given a warm welcome as she was introduced to a three-quarters full stadium.

But she looked unsure in the warmup and it spilled over into the match. Her sister Venus, who returned from a hip injury after five months away, began her match Monday with two double-faults. Serena opened her first service game with one of her own.

Pironkova, who reached the semifinal at Wimbledon last year but had won only four matches this year, showed no sympathy to her opponent's predicament by using fierce groundstrokes.

After trailing 4-0, Williams smacked her racket into the turf in disgust. On winning her first game to make it 5-1, the former top-ranked player heard the rare sound of sympathetic applause.

The unseeded Bulgarian then took the set with a forehand winner.

Soon Williams began to look — and sound — more like her old self. She increasingly greeted her winners, and an improving first serve, with determined cries of "c'mon."

Leading 5-3 in the second set, she fell 0-30 down but responded with a 120 mph ace down the middle and a 114 mph ace out wide.

Williams was still below her best in the third as Pironkova's flat groundstrokes continued to do damage. She rallied to 2-2, but the unseeded Williams immediately broke again and had a chance to serve it out at 5-4.

In the final game, Williams was warned about taking too much time between points — much to her annoyance — but the Wimbledon champion kept her cool to seal a valuable victory. She's looking to regain her form ahead of the defense of her Wimbledon title.

In other matches, Ana Ivanovic advanced to a second-round meeting with Venus Williams with a 6-4, 6-3 win over Julia Goerges of Germany.

The former No. 1-ranked Serb won her last two events of 2010, but she has struggled and lost in the first round in four of her 10 tournaments this season. Her semifinal last week in Birmingham was her first of the year.

"I don't expect myself to go out there and play great every match," Ivanovic said. "I just expect myself to work hard. But it's hard. I do have to think about going back to basics for a moment and trying to get the practice in, trying to stay healthy and trying to stay basically on top of small things."

Defending champion Ekaterina Makarova labored to a 6-1, 3-6, 6-4 win over Croatian qualifier Mirjana Lucic. French Open runner-up Francesca Schiavone advanced with a 7-6 (7), 6-1 win over Kaia Kanepi.

In the men's tournament, American qualifier Donald Young beat Briton Daniel Cox, 6-1, 7-5. Fourth-seeded Spaniard Guillermo Garcia-Lopez was upset 6-3, 6-4 by India's Somdev Devvarman, and South African Kevin Anderson defeated Britain's Alexander Slabinsky.