MELBOURNE (AFP) - World number one Justine Henin and fifth seed Maria Sharapova will collide in the Australian Open quarter-finals after mauling their fourth round opponents Sunday.

Defending champion Serena Williams also flexed her muscles in a one-sided affair to set up a quarter-final with third seed Jelena Jankovic, who was again unconvincing as she struggled to finish off Australian hope Casey Dellacqua.

Belgian top seed Henin clinically dispatched Taiwan's Hsieh Su-Wei 6-2, 6-2 to take her match winning streak to 32.

The French and US Open champion said she was relishing the prospect of facing elite opposition as the second week of the season-opening Grand Slam looms.

"Now it's like another tournament is going to start, it's going to be another level," she said.

The seven-time Grand Slam champion dominated Hsieh from the outset, needing only one hour 14 minutes to down the qualifier, ranked 158 in the world.

Sharapova's task against 11th seed Elena Dementieva was supposed to be more difficult but the Russian needed only 62 minutes to see off her compatriot and produced an even more emphatic 6-2, 6-0 scoreline.

The 20-year-old is on a quest to make amends for last year's humiliating loss in the final to Serena Williams and was in scintillating form as she downed Dementieva

"I was seeing the ball well today," Sharapova said, acknowledging she was likely to have a tougher time against Henin.

"She's just very steady and very consistent and she do whatever it takes to win the point," she said.

"No matter how long the point is, no matter how many times you run her side to side, she's willing to be out there challenge you to make the errors."

The winner of the Henin-Sharapova match may well play Serena Williams, who is starting to put together a campaign that has remarkable similarities to last year's stunning title win.

Williams has bounced back from a shaky opening match to improve with every round and on Sunday eliminated Czech 12th seed Nicole Vaidisova, who she beat in the semi-final in 2007.

She will face Jankovic in the quarter-finals with memories of the straight sets thrashing she handed the Serb at the same stage last year.

The eight-time Grand Slam champion said there was still room for improvement after her 6-3, 6-4 win over Vaidisova.

"I felt like I didn't have a lot of rhythm out there," Williams said. "I felt like lazy, like I wasn't moving the way I wanted to."

Jankovic admitted the prospect of facing a fully-motivated Williams was daunting after another lacklustre display in which she struggled to finish off hometown heroine Dellacqua in front of a partisan Melbourne Park crowd.

"Whoa, it'll be a tough one," she said after finally downing Dellacqua 7-6 (7/3), 6-1.

Jankovic's tournament lead-in was disrupted by injury and she failed to fire in the opening rounds, which have included two draining three set matches.

She acknowledged that she needed to drastically improve to have any hope of downing Williams.

"She's stronger than me, twice my size, so it's not so easy," the 22-year-old said.

"Sometimes I feel like she's going to blow me off the court.