Stuttgart - Dinara Safina clobbered Sara Errani 6-0, 6-1 in her first match as world number one tennis player on Tuesday night for a place in the second round of the Porsche Grand Prix. Safina took just 51 minutes to win the lopsided contest, clinching victory with an ace against the 37th-ranked Errani.

Safina, who turned 23 on Monday, dethroned Serena Williams at the top of the rankings last week. It was also her first match on clay of the season.

Fellow-Russian Olympic champion Elena Dementieva had to fight harder before also advancing, 6-4, 3-6, 6-3 against Anna-Lena Groenefeld.

Safina and Dementieva lead six top ten players in Stuttgart which is the first WTA clay court tournament held indoors. Not present from the top players are the Williams sisters Venus and Serena.

"I was quite nervous before the match. I tried to do everything right and to stay focussed. It went according to plan," said Safina.

Playing as number one was a new experience for her, but Errani was no serious threat and only got on the scorebaord in the fourth game of the second set. Safina fired five aces overall and did not face a break point.

The second-seeded Dementieva, meanwhile, threw away a 3-1 lead in the second set as she lost five games and Groenefeld locked the sets at 1-1 with a forehand winner. But Dementieva regrouped, broke for 3-1 and took the first-round win in 2:01 hours on a service winner.

"It was a difficult match to play, with lots of ups and downs. I lost my concentration (in the second set)," said Dementieva. "The first match is always difficult to play. I hope to play better in the next match."

Earlier, seventh-seeded Caroline Wozniacki, a Dane of Polish descent, defeated Czech player Iveta Benesova for the second time in as many meetings, 6-3, 7-5.

Wozniacki got the last of a dozen breaks for a 6-5 lead in the second set. She then double faulted on second match point in the next game, but wrapped up matters after 90 minutes of play when Benesova hit a groundstroke long.

"I am happy I pulled through. I didn't give up," said Wozniacki.

Polish eight seed Agnieszka Radwanska also improved to 2-0 against Canada's Aleksandra Wozniak after surviving a first-set scare, 7-6 (7-2), 6-0 in 77 minutes.

Radwanska next plays Tsvetana Pironkova of Bulgaria who ousted Italy's Alberta Brianti, 0-6, 6-4, 6-4. Agnes Szavay of Hungary outlasted Japan's Ai Sugiyama 6-3, 2-6, 7-6 (7-4) to meet Dementieva.(dpa)