Chellsie Memmel of the United States continued to set the qualification pace for the women's all around final at the world gymnastics championships in Melbourne on Wednesday.

Considered a leading medal contender along with team mate Nastia Liukin, the 17-year-old 2003 uneven bars world co-champion took part in the first qualifying sub-division and top-scored with 9.550 on the uneven bars to finish on 37.412.

Suzanne Harmes of the Netherlands was in second place overall after the second sub-division on 35.849 points, with Germany's [Images] Daria Bijak in third on 35.600.

China's Athens Olympics [Images] all around bronze medallist Zhang Nan placed herself in jeopardy of missing out on the final when she fell from the parallel bars and then stopped during the routine to score just 7.400.

She recorded an 8.975 on the vault and is to complete her qualification on the floor and beam in the fourth sub-division later on Wednesday, but could miss out on the top-24 required to qualify for the all around final on Friday.

Brazil's [Images] 2003 floor champion Daiane Dos Santos produced a scintillating performance to record the highest score in her best discipline with 9.550.

Set to salsa music, Dos Santos smouldered her way through a virtually flawless routine that enraptured the small crowd, who produced the loudest cheer of the first session when the 22-year-old finished.

"It could have been better but I am happy with my performance," she said.

"I took a couple of steps on one of my landings so I can improve but I'm happy with that.

"I'm confident [of defending the title]. I did well in qualifying and I'm feeling prepared."

Alicia Sacramone of the US proved that Dos Santos could not take the title for granted with a superb performance to record 9.500, while Memmel was in third on 9.362.

SUPERB VAULTS

Athens triple gold medallist Catalina Ponor also produced a high-tempo routine though is in danger of missing the top-eight qualifiers for the floor final at the weekend after she recorded a 9.200 to stand sixth with two sub-divisions still to come.

The 18-year-old Sacramone also produced a superb pair of vaults to record an average of 9.468, ahead of British pair Imogen Cairns (9.081) and Shavahn Church (9.062).

Romania's Ponor, who won the gold medal on the beam at Athens, produced a double back somersault to end her routine on the apparatus and led qualification with a score of 9.562.

Russia's [Images] Yulia Lozhechko was in second place with 9.337, while Memmel was in third on 9.200

The American also led the uneven bars on 9.550, with Russia's Polina Miller in second on 9.437 and Japan's [Images] Mayu Kuroda in third on the same score.

The local crowd, spurred on by the success of the men on Tuesday when three competitors qualified for finals, were not disappointed by Australia's Olivia Vivian, who recorded the seventh-best score on the uneven bars with 9.312.

The world championships are the 16-year-old Australian's first international competition.