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.
Sharapova breaks new ground
It took two hours and 14 minutes for the five-time Grand Slam champion to see off Davis, the world number 103, and claim the 600th victory of her 15-year career.
“Wow. I’ve won 600 matches?” said the 28-year-old. “Is this like a friendly reminder that I’m getting old? Might be.”
Sharapova next faces a tough test against 18-year-old Bencic, with the winner earning a potential quarter-final against Williams.