SYDNEY - AN UNQUENCHABLE self-belief burns deep within Serena Williams even after her straight sets pounding by rival Elena Dementieva in the semi-finals of the Sydney WTA International on Thursday.

The fiercely-competitive American, chasing her 10th grand slam title in next week's Australian Open in Melbourne, was lethargic and off her game as the Russian world number four romped to a 6-3, 6-1 victory.

Serena, the younger half of the charismatic Williams double-act with sister Venus, is grudging in her praise of others and indomitable in her belief of her own powers.

Asked if she thought number one-ranked Jelena Jankovic was genuinely the best player in the world, Williams bristled at the questioner at her post-match press conference Thursday.

'Best player, pardon? Oh, no. I don't think anyone is better than (me) .... I would feel crazy sitting here being a professional tennis player and saying that someone is better than me,' she said.

'Yeah, she's ranked higher than me. I don't care if I was 1,000 in the world, I would still feel like I was the best. You know, that's just me trying to be positive with myself. Hopefully she feels that way herself.

'For me, I believe in me. I don't believe anyone's better than me. When I talk to Venus she says the same thing.'

And who is the women's favourite for the Australian Open? 'Obviously, myself and Venus. You know, probably the top four ranked players. So, yeah,' she said.

Dementieva, on a nine-match winning run, lines up against fellow Russian Dinara Safina in Friday's Sydney final.

Williams saved three match points to win a torrid three-setter against Danish teenager Caroline Wozniacki in her Sydney quarter-final Wednesday after having saved four in her first-round win over Australian Samantha Stosur.

Leading into Thursday's semi-final, Williams possessed the stunning statistic of battling back from match point down and going on to win eight times in her career, five of them in Australia.

And only once before Thursday had Williams failed to go on and win the tournament from that position. -- AFP