Amelie Mauresmo suffered a setback in the build up to her Australian Open title defence on Wednesday when the Frenchwoman was knocked out of the Sydney International, the final event before the opening Grand Slam of the season.

Russia's Nikolay Davydenko also had a day to forget and the world number three is in danger of missing next week's event in Melbourne after picking up a suspected stress fracture.

Mauresmo's hopes of getting in some valuable match practice before she defends her title ended when she bundled out in the quarter-finals by in-form Serb Jelena Jankovic.

The world number three had started the match as a overwhelming favourite but crashed to a 7-5, 6-0 defeat in just over an hour.

"I would have loved of course to play one or two more matches but I know there's still work to do," she said.

Jankovic followed up her title win in last week's Auckland Classic with her eighth straight victory this year to suddenly loom as a serious contender for the Open.

"I've worked really hard and I feel really prepared and I have the confidence," she said.

"I'm really enjoying my game and I have no fear. I feel I can beat anybody and that's important."

Davydenko told a news conference doctors had ordered him to undergo an MRI scan to determine the extent of the damage after he limped off the court with a foot injury.

The Russian lost the first set of his second-round clash with Frenchman Paul-Henri Mathieu 6-4 on Wednesday before the pain became too overbearing.

"The doctor said it might be a stress fracture," Davydenko told a news conference. "But it is not like 100 percent, that's why I need to check."

Davydenko was the latest in a series of high-profile players to pull out of the Sydney event and offered a blunt explanation on the reason.

"Because it's a small tournament," he said. I don't think nobody care about here."

IMPRESSIVE CLIJSTERS  

While Mauresmo and Davydenko made their exits, former Australian Open finalists Kim Clijsters and Marcos Baghdatis signalled their intentions with impressive victories.

Clijsters sailed past Israel's Shahar Peer 6-2, 6-1 to join China's Li Na in the women's semi-finals, while Baghdatis booked his place in the men's quarter-finals with a 6-4, 6-7, 6-3 victory over Czech Jan Hernych.

Defending champion James Blake also advanced to the last eight with a comfortable 6-2, 6-4 win over Australian wildcard Nathan Healey while Russian lucky loser Evgeny Korolev kept his unlikely run going by beating Robby Ginepri 0-6, 6-4, 6-4.

Clijsters, who was runner-up to fellow Belgian Justine Henin-Hardenne at the 2004 Australian Open, beat Peer so easily that she was able to use the match as practice.

"There's still a lot of things I feel like I can improve on, but I didn't really get tested today," she told a news conference.

"When you play a match like this, you don't really look at your opponent, you just try to work things out yourself.

"I served the best I have on the whole trip so that was good... things are gradually getting better and better."

Baghdatis, whose fairytale run to last year's Australian Open final brought the tournament to life, was given a tough workout from Hernych.

The charismatic Cypriot surprised his followers when he arrived on Sydney's Olympic Park centre court without his trademark beard and briefly gave them cause to worry before raising his game in the final set.

"It wasn't easy. It was hot out there and it's the first time I've played in the heat for a while so it was good to have a match like that before the Open."

Baghdatis plays Carlos Moya in Thursday's quarter-finals after the former world number one saved a match point in his 4-6, 7-6, 6-3 win over fellow Spaniard Fernando Verdasco.