PARIS (AFP) - Serena Williams began her third stint as world number one with a straightforward 6-1, 6-4 victory over Czech left-hander Iveta Benesova in the first round of the WTA Paris Open on Wednesday.

Williams returned to the top of the women's world rankings when she won last month's Australian Open, and she looked in good shape here as she set up a second round encounter with Croatian qualifier Karolina Sprem.

"I was okay. I wasn't great, but I was so glad to win," Williams said.

"This was a little better than Australia, because I didn't play well in my first two rounds there."

The American made an uncertain start, double-faulting twice and having to save two break points in her opening service game, before breaking Benesova in the third game and running away with the first set in just 19 minutes.

Benesova, the world number 34, broke her opponent in the first game of the second set when Williams put a forehand into the tramlines at 30-40, but the top seed fought back from 40-0 down in the next game to break back immediately.

Williams was then forced to save a break point in the third game as Benesova found her rhythm with some incisive groundstrokes, but the 10-time Grand Slam-winner eventually secured the match-winning break in game 10.

"She raised her game and I made some key errors on some key points," Williams said.

"But then I was able to get a little confidence and that's pretty much what happened."

Earlier, Swiss sixth seed Patty Schnyder booked her place in the second round with a 6-4, 7-6 (7/3) victory over Ukrainian Alona Bondarenko.

Schnyder, the world number 16, will meet French wild card Nathalie Dechy in the next round.