Melbourne: Novak Djokovic and Serena Williams proceed further in the Australian Open on Thursday whereas Wimbledon champion Petra Kvitova flirted with disaster.
    
Defending champion Djokovic thumped Colombia's Santiago Giraldo and Williams brought up her 500th career win, against Barbora Zahlavova Strycova, to reach the third round.
    
Former champion Maria Sharapova made it two wins for the loss of just two games, and 2008 French Open winner Ana Ivanovic also strolled through to the weekend fixtures.
    
Second seed Kvitova had a trickier assignment against battle-hardened Carla Suarez Navarro, but she survived a mid-match meltdown to progress in three sets -- and stay on course for the top world ranking.
    
Djokovic has been in commanding form at the year's first major as he bids to repeat last season's astonishing haul of three grand slams among 10 titles, with a 41-match winning streak along the way.
    
And the Serb expended little energy in his 6-3, 6-2, 6-1 hit-out against Giraldo as he speeds towards an expected semi-final with Andy Murray, his victim in last year's final, who plays later.
    
"I try to not underestimate any opponents in early rounds," Djokovic said.
    
"Santiago came out early hitting the ball quite flat. But I knew that, you know, sooner or later he's going to drop the rhythm and I just have to hang in there. I've done a good job," he added.
    
Williams's victory kept up her record of reaching the third round in all but one of her 47 grand slams -- despite a heavy fall late in the match on her recently injured ankle.
    
"It's fine, I just have really wobbly ankles," she said. "I wasn't meant to be a ballerina."

(Agencies)