Novak Djokovic led a trail of the top men's seeds into the second round at the Australian Open on Tuesday as Stan Wawrinka made a successful return to his life-changing court.

World number one Djokovic, fighting off the effects of a virus, put paid to Aljaz Bedene in straight sets as he begun his quest for a fifth title at Melbourne Park.

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The Serb top seed ousted the 116th-ranked Slovenian 6-3, 6-2, 6-4 in 1hr 49min on Rod Laver Arena and will next play Russian Andrey Kuznetsov.

Djokovic, who crashed out to eventual winner Wawrinka in the quarter-finals of last year's event, has been dogged by illness in the lead-up to the year's first major tournament.

But after encountering early problems from the 116th-ranked Bedene he went on to secure passage into the next round.

The seven-time Grand Slam champion broke Bedene's service four times and only had three break points against his serve in the match.

"For a first round performance it was pretty good, obviously I still need to work on a few things, I'm still developing my game," Djokovic said.

Wawrinka returned to Rod Laver Arena where his life changed completely last year to get his title defence off to the right start.

The Swiss fourth seed ripped through Turkey's Marsel Ilhan 6-1, 6-4, 6-2 to safely negotiate the first hurdle.

Wawrinka had few problems breaking the 100th-ranked Ilhan's serve five times and will play Romanian Marius Copil next up.

The big-serving Swiss has now not lost in the first round in 10 appearances at the Australian Open.

Elsewhere, Kei Nishikori took the first steps he hopes will lead to Grand Slam glory with a hard-fought opening win over Spaniard Nicolas Almagro.

Nishikori, who lost to Marin Cilic in last year's US Open final, won a 2hr 7min dogfight with the former world number nine before prevailing, 6-4, 7-6 (7/1), 6-2 on Margaret Court Arena.

The fifth seed had a battle with Almagro before winning a pivotal second-set tiebreaker and sweeping through the third and final set for passage into the second round.

Another of the new breed, Canada's boom-serving Milos Raonic, was taken to two tiebreak sets before overcoming Ukraine qualifier Illya Marchaneko.

Other seeded winners included Spanish pair David Ferrer and Feliciano Lopez, Frenchman Gilles Simon and American John Isner, while Australian Lleyton Hewitt, playing in his 19th straight national open, beat China's Zhang Ze in four sets.