Holding the No. 1 ranking in tennis is undoubtedly an honor. It also brings a lot of questions for a player who has yet to win a Grand Slam tournament.

Caroline Wozniacki started the Australian Open as the top-ranked woman after winning six tournaments last year. The 20-year-old Dane has reached a Grand Slam final just once, losing the U.S. Open to Serena Williams in 2009.

She is not alone in this regard.

No. 2 Vera Zvonareva of Russia reached her first two Grand Slam finals last year but hasn't yet hoisted a trophy. Russia's Dinara Safina was No. 1 in 2009 and Serbia's Jelena Jankovic ascended to the top in 2008. Neither has a major title.

Safina made it to three major finals, including the 2009 Australian Open title match. On Tuesday night, she lost 6-0, 6-0 to U.S. Open champion Kim Clijsters in the first round of the Australian Open, describing it as an embarrassment.

Clijsters, who lost three Grand Slam finals before finally cracking a major at the U.S. Open in 2005, can empathize with players struggling to turn a top ranking into a championship at one the sport's four majors.

"She didn't get to No. 1 just by luck, so that game is still there," Clijsters said, referring to Safina. "She needs to win a few matches to build up her confidence."

Wozniacki insists she has nothing to prove ad says the No. 1 ranking has given her a good feeling about the Australian Open.

Jankovic was in a similar situation to Wozniacki 2½ years ago. She doesn't think a top ranking creates greater pressure to win.

"Always the same questions!" Jankovic said Tuesday after her first-round victory at Melbourne Park, where she was asked how Wozniacki's circumstances compared with her experience. "I mean, what kind of pressure?"

Still, she hinted that a title at a Grand Slam tournament can outweigh the more fleeting status of a No. 1 ranking.

"It's a Grand Slam and everybody wants to win it," she said. "I think every player has extra motivation when they're playing a Grand Slam because they want to really win it. Doesn't matter if you're No. 1 or not."

Wozniacki will remain No. 1 as long as she doesn't slump badly in the coming days. She has a comfortable draw until the semifinals, where she could meet fourth-seeded Venus Williams, the seven-time Grand Slam title winner who opened with a straight-sets win over Argentina's Gisela Dulko.

Only Zvonareva and third-ranked Clijsters can win enough points at Melbourne Park to challenge for the top ranking, and even then a change at the top would be difficult. If Wozniacki reaches the semis, her top ranking is unassailable. If she reaches the fourth round, Clijsters or Zvonareva must win the tournament to take the top spot.

The women's field at the Australian Open is more open than it has been in years, in part because defending champion Serena Williams withdrew with a foot injury. She has won 13 Grand Slam singles titles and considers those more important than the rankings as a gauge of top players.

Just three of the top 10 seeded women in Melbourne have won Grand Slam titles — Williams (7), Clijsters (3) and Italy's Francesca Schiavone (1). Four of the top 10 men's seeds have major titles — Rafael Nadal and Roger Federer dominate with 25 between them, and one each for Andy Roddick and Novak Djokovic.

Zvonareva, who had an easy first-round victory Tuesday over Austria's Sybille Bammer, spoke for many when asked about gaining a No. 1 ranking without a major title.

"I'm a tennis player, and my job is to play tennis," she said. "So I go out there, I try my best in every single match. If I win, that's great. If I have some losses, well, I try to take something out of it and try to go back on the court and work even harder."

But what is more important, reaching No. 1 or winning a Grand Slam tournament?

"Either thing is great," she said. "I mean, I wouldn't find a player who would say, 'I don't want to be No. 1 in the world,' or, 'I don't want to win a Grand Slam.' Everyone wants to be No. 1. Everyone wants to win Grand Slams. In order to do so, you have to win matches — you have to win a lot of matches. That's what I'm trying to do. That's it."