Djokovic, Williams begin Australian Open title defence with easy wins

Serena Williams of the US hits a shot during her first round match against Italy's Camila Giorgi at the Australian Open tennis tournament at Melbourne Park, Australia, January 18, 2016. [Photo/Agencies]

Earlier on RLA, two-time Wimbledon champion Petra Kvitova made light work of Thailand's highest ranked female Luksika Kumkhun, who caused a shock upset against her more fancied opponent at the same event in 2014.

There would be no repeat of Kvitova's untimely exit two years ago, as she cruised to a 6-3, 6-1 victory in an hour and 10 minutes.

The sixth-seed from Belarus showed no signs of the glandular fever that forced her to retire in the first round of the Shenzhen Open a fortnight ago.

Elsewhere, Australian Daria Gavrilova became the first local player to progress to the second round with a 7-6 (7-3), 6-4 win over Czech player Lucie Hradecka.

Recently, Gavrilova teamed up with fellow Australian Nick Kyrgios to clinch Australia's first Hopman Cup win in 19 years.

"I was as nervous today as I was at (the) Hopman Cup," Gavrilova told reporters on Monday.

"All these matches mean a lot to me ... it was hard serving it out in the end. I got a bit nervous."

It was the 21-year-old's first Grand Slam win on Australian soil since she secured citizenship in 2013.

The Russian-born world Number 39 said the home town support played a major part in her first win at the Australian Open.

"It was amazing. Someone yelled out 'break here' and I actually did break the same game," she said. "I was like 'oh, thanks'."

Gavrilova will face Kvitova in the second round.

On Hisense Arena, Japan's Kei Nishikori easily accounted German Philipp Kohlschreiber 6-4, 6-3, 6-3, in what many considered a danger game for Asia's highest ranked player.

Other top players to steamroll into the second round with straight sets wins included: Agnieszka Radwanska (6-2, 6-3), Tomas Berdych (6-4, 6-3, 6-3) and Carla Suárez Navarro (7-5, 6-4).

Overall, Chinese players turned out mixed performances on Day 1.

Chinese qualifier Wang Qiang pulled off one of the biggest heists of the opening day, defeating 2013 semi-finalist Sloane Stephens 6-3, 6-3.

Despite winning the second set, compatriot Wang Yafan crashed out 6-4, 1-6, 6-3.

Meanwhile, China's only player in the men's draw, 24-year-old Wu Di, failed to progress to the second round in his third appearance at the Australian Open, losing in straight sets.