World number one Diede de Groot of The Netherlands begun her defence of the Australian Open women's wheelchair title with victory over Britain's Lucy Shuker.
De Groot eased past Shuker at Melbourne Park, defeating her opponent 6-0, 6-0 in just 38 minutes.
The defending champion will now play compatriot Marjolein Buis in the semi-final, who beat Germany's Sabine Ellerbrock 6-1, 6-4.
The competition's second seed, Japan's Yui Kamiji, had a tougher challenge against Italy's Guilia Capocci, eventually winning 7-6, 6-3.
She will face Aniek van Koot of The Netherlands in the next round, after the Dutch player defeated South Africa's Kgothatso Montjane 6-1, 7-5.
The defending champion in the men's competition was also successful.
Japan's Shingo Kunieda was facing Great Britain's Alfie Hewett in the opening tie, in what was a rematch of last September's US Open final.
Kunieda reversed the outcome of that match, beating Hewett 6-1, 6-4.
The Japanese player will now meet Stefan Olsson in the semi-finals after the Swede defeated his doubles partner Joachim Gerard 6-4, 6-3.
World number two, Gustavo Fernandez of Argentina, comfortably won against wildcard Ben Weekes of Australia 6-1, 6-1.
Fernandez will play France's Stephane Houdet in the semis, who eventually beat Britain's Gordon Reid 7-6, 5-7, 6-2.
In the quad singles event, world number one Dylan Alcott of Australia defeated compatriot and wildcard Heath Davidson 6-3, 6-2.
David Wagner of the United States needed three sets to overcome Britain's Andy Lapthorne 6-1, 4-6, 6-4.
All four quads players are competing in a round-robin.