Big guns cruise

Defending champions Novak Djokovic and Serena Williams stormed into the Australian Open third round on Wednesday as tennis authorities came under fire over their efforts to fight match-fixing.

Djokovic had a third-set tussle with French teenager Quentin Halys before winning their night match 6-1, 6-2, 7-6 (7/3), joining Williams and Roger Federer in the next stage.

As a match-fixing controversy continued to reverberate at Melbourne Park, Williams swatted Hsieh Su-Wei 6-1, 6-2 to reach the third round as she seeks a record-equalling 22nd major title.

Williams eased lingering concerns over the state of her injured knee as she obliterated the Taiwanese, even pulling off possibly her first ever round-the-net shot for good measure.

Federer, who is trying to extend his record number of Grand Slam crowns to 18, then dismantled his 35th-ranked practice partner Alexandr Dolgopolov 6-3, 7-5, 6-1.

Separately a senior anti-corruption official told AFP that match-fixing was commonplace in tennis's lower levels and criticised the "opaque and secretive" Tennis Integrity Unit, which is tasked with finding cheats.

Chris Eaton, director of integrity at the International Centre for Sport Security in Doha, was speaking after a report claimed several players suspected of being serial match-fixers had never been punished.

"Integrity is by definition open and transparent. The TIU is neither... by operating in the shadows they fail to practice what they preach," he said, calling for a "new independent and integrated integrity model".

The controversy is just the latest to hit the tainted sports world after claims of a doping cover-up shook athletics and multiple scandals engulfed football's governing body, FIFA.

Petra Kvitova became the latest women's top-10 player to fall, joining Simona Halep and Venus Williams on the sidelines when she was shocked 6-4, 6-4 by Australian giant-killer Daria Gavrilova.

In a positive evening for the hosts, the combustible Nick Kyrgios overcame a mix-up with his shorts to beat Pablo Cuevas and set up a showdown with world number six Tomas Berdych.

Agnieszka Radwanska's sky-high confidence took another leap upwards when she halted Eugenie Bouchard, back in form after suffering concussion at the US Open, 6-4, 6-2.

On court earlier was five-time Grand Slam champion Maria Sharapova, who had little difficulty dispatching 105th-ranked Aliaksandra Sasnovich 6-2, 6-1.

Japanese seventh seed Kei Nishikori beat his close friend Austin Krajicek 6-3, 7-6 (7/5), 6-3 as he pressed his bid for a first Grand Slam title.