(CNN) -- 2007 champion Serena Williams marched into the fourth round of the Australian Open with a 6-1 6-4 win over Shua Peng of China on Saturday.
Suarez Navarro celebrates another fine win in her impressive run in Australia.
Serena is the only Williams left in the draw after the shock exit of her sister Venus to Carla Suarez Navarro of Spain in the second round, and admits it is an added spur.
"It obviously increases my motivation and my desire to win, and hopefully to do better," she was quoted on the official tournament Web site www.australianopen.com.
Williams, who has won the opening grand slam of the season in alternate years since 2003, was never seriously troubled by Peng, but found herself an early break down in the second set.
It was immediately retrieved only for Peng to break again for 3-1.
Once again Williams broke back and won five of the next six games to wrap up victory.
"I'm feeling a little rusty, for whatever reason. I'm hoping my next round, I'll be a little better," she added.
Victoria Azarenka of Belarus awaits after the 13th seed saw off the challenge of former champion Amelie Mauresmo 6-4 6-2.
Suarez Navarro continued her surprise run by beating compatriot Maria Jose Martinez Sanchez 6-1 6-4.
She will play another Spaniard in the fourth round after Anabel Medina Garrigues, the 21st seed, upset 12th seed Flavia Pennetta, of Italy, 6-4 6-1.
Russian Elena Dementieva, who came into the Australian Open off the back of wins in Auckland and Sydney, beat home hope Samantha Stosur 7-6 6-4 in a close night match.
Fourth seed Dementieva plays 18th seed Dominika Cibulkova, who beat Virginie Razzano 7-5 7-5 to set up their fourth-round clash.
Elsewhere, China's Jie Zheng reached the fourth round in Melbourne for the first time with a 6-2 6-2 victory against Kateryna Bondarenko of the Ukraine.
It proved a tough day for the Bondarenko's as Kateryna's sister Alona, the 31st seed, also went out, going down 7-6 6-4 to revitalized eighth seed Svetlana Kuznetsova, of Russia, who will now play Zheng.