London: Defending champion Serena Williams needed another three-setter to reach the Wimbledon third round on Thursday while former number one Ana Ivanovic barely broke sweat in her last 64 encounter.
Four-time champion Williams came back from a set down to defeat Romanian teenager Simona Halep 3-6, 6-2, 6-1.
But the 29-year-old still looked ring-rusty, playing just her fourth match since returning from an 11-month lay-off where she recovered from a foot injury as well as life-threatening blood clots on her lungs.
"I`m hoping to get better as the event goes on," said seventh seed Williams, who had broken down in tears after her first round win against Aravane Rezai.
"It was really windy out there in the first set. I was tight and I told myself to relax more. I need to play longer matches and get more practice."
The American had been overshadowed by world number 58 Halep in the first set, the Romanian 19-year-old showing off the freedom of movement afforded her by a decision to undergo breast reduction surgery two years ago.
Williams`s reward for her victory is a last 32 clash against either Russia`s Maria Kirilenko or Thai veteran Tamarine Tanasugarn.
Serbian 18th seed Ana Ivanovic, the 2008 French Open champion and who made the semi-finals at Wimbledon in 2007, eased past Greek world number 121 Eleni Daniilidou 6-3, 6-0.
The 23-year-old next faces either Poland`s Agnieszka Radwanska or Petra Cetkovska of the Czech Republic for a place in the last 16.
"I think lots of players tend to peak for this event. It`s one of the biggest tournaments in the world," said Ivanovic, who has only dropped just four games in the first two rounds.
"I`m just very happy to manage to win a few matches. I had a good week in Birmingham, then played well in Eastbourne, it helps and builds up for Wimbledon."
Svetlana Kuznetsova, the Russian 12th seed and a two-time Grand Slam title winner, beat Romania`s Alexandra Dulgheru 6-0, 6-2 to set up a meeting with Belgium`s Yanina Wickmayer, the 19th seed.
Francesca Schiavone, the sixth seed and 2010 Roland Garros winner, was also an early winner beating Barbora Zahlavova Strycova of the Czech Republic 7-5, 6-3.
Later Thursday, China`s French Open winner and third seed Li Na faces German wildcard Sabine Lisicki.
Top seed and world number one Caroline Wozniacki aims to defeat France`s Virginie Razzano, the world number 96, who is playing Wimbledon to fulfill the death bed wish of fiance and coach Stephane Vidal, who died from a brain tumour in May.
Russia`s 2004 champion Maria Sharapova, the fifth seed, tackles 17-year-old British wildcard Laura Robson, who won the 2008 junior championship.