Serena Williams has dismissed any hint of match-fixing in women’s tennis after surviving a tough early test to safely progress to the second round of the Australian Open at Melbourne Park.

While there’s been no suggestion of any such sinister behaviour on her tour as the ATP deals with fresh stories of fixing in men’s tennis, Williams made it clear on Monday that throwing anything but a ball toss wasn’t in her DNA.

“When I’m playing, and I can only answer for me, I play very hard and every player I play seems to play hard,” the 21-time grand slam champion said after her 6-4 7-5 win over Italian Camila Giorgi.

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“As an athlete, I do everything I can to be not only great but historic.

“If that’s going on, I don’t know about it. I’m kind of sometimes in a little bit of a bubble.”

A knee injury had prevented Williams from completing a competitive match since the US Open in September, but the American was relieved to come through unscathed against Giorgi to book a second-round meeting on Wednesday with Taiwan’s Su-Wei Hsieh.

“It’s great. It was an hour and 43 minutes and I didn’t feel it at all,” said the top seed.

“It wasn’t very easy. She obviously plays very well and knows how to play the shots.

“I haven’t played a competitive match in a long while but it was really good.

“It wasn’t quick so that worked to my advantage. I was able to stay in it and stay calm today and that’s what matters most.”

Second seed Maria Sharapova, last year’s runner-up to Williams, and two-time Wimbledon champion Petra Kvitova also dispelled any lingering fitness doubts with straight-set first-round wins.

Sixth-seeded Kvitova was the first player through to the second round after crushing Thai qualifier Luksika Kumkhum 6-3 6-1 in the opening match of the tournament at Rod Laver Arena.

Kvitova pulled out of last week’s Sydney International with gastro, having also retired mid-match during the first round in Shenzhen earlier this month, her only other appearance since the Fed Cup final in November.

“But I’m feeling much better now,” Kvitova said after setting up a date on Wednesday with Australian young gun Daria Gavrilova, a 7-6 (6-3) 6-4 victor over Czech Lucie Hradecka.

Fifth-seeded Sharapova had been under an injury cloud after withdrawing from the Brisbane International with a forearm problem, but needed only 73 minute to account for Japan’s Nao Hibino 6-1 6-3.

Fourth seed Agnieszka Radwanska, 10th seed Carla Suarez, highly-rated teenage 12th seed Belinda Bencic, Williams’ US Open conquerer Roberta Vinci, seeded 13th, and Canadian starlet Eugenie Bouchard, a semi-finalist two years ago, also advanced on Monday.

But three well-credentialled seeds crashed out, including former world No.1 Caroline Wozniacki.

The Dane was cruising at a set and a service break up before capitulating in a 1-6 7-6 (7-3) 6-4 loss to Kazakhstan youngster Yulia Putintseva.

“It’s a pretty s****y start to the season. It wasn’t a pretty first set but I got it done and really should have closed it off in two,” Wozniacki lamented.

Russian Margarita Gasparyan removed former French Open finalist Sara Errani, seeded 17th, 1-6 7-5 6-1, while Chinese qualifier Wang Qiang ousted American 24th seed Sloane Stephens, a semi-finalist in 2013 and winner of the season-opening Auckland Classic, 6-3 6-3.

– AAP