Former champion Maria Sharapova needed three sets to beat unseeded American Lauren Davis and reach the last 16 at the Australian Open.
The Russian fifth seed won 6-1 6-7 (5-7) 6-0 under the Rod Laver Arena roof, as rain halted play on outside courts.
Twelfth seed Belinda Bencic and men's seventh seed Kei Nishikori progressed.
Roger Federer takes on Grigor Dimitrov later on Friday, with Novak Djokovic and Serena Williams featuring in the night session at Melbourne Park.
Switzerland's Bencic beat Kateryna Bondarenko of Ukraine 4-6 6-2 6-4, while Nishikori saw off Spain's Guillermo Garcia-Lopez 7-5 2-6 6-3 6-4.