World No.1 Novak Djokovic dispelled any concerns about his health by powering into the second round of the Australian Open on Tuesday.

The four-time Open champ had been troubled by a virus in the leadup to the first major of the year, but he showed no after-effects in a regulation 6-3 6-2 6-4 victory over Slovenian qualifier Aljaz Bedene.

“It’s been a rough two weeks for me but I’m getting there,” said Djokovic.

“For a first-up performance it was pretty good.”

The Serb won six titles in 2014 including the year-end championship in London, but started this year with a surprise semi-final loss to Ivo Karlovic in Doha.

Switzerland’s Stan Wawrinka made a flying start to his Australian Open title defence, crushing Turkey’s Marcel Ilhan in straight sets.

Wawrinka broke through for his maiden grand slam title last year at Melbourne Park, beating Djokovic in the quarters and Rafael Nadal in the final.

The No.4 seed could not have been more impressive on Tuesday, smashing Ilhan 6-1 6-4 6-2.

Japanese fifth seed Kei Nishikori also eased through to the second round with a regulation win over Spanish veteran Nicolas Almagro.

Playing in his first major since his thrilling run to last year’s US Open final, the Japanese star proved too good for Almagro, winning 6-4 7-6 (7-1) 6-2.

He will play Croatian Ivan Dodig or Brazil’s Joao Souza in the second round.

Nishikori has advanced at least to the fourth round at each of the previous three Australian Opens and will fancy his chances of again going deep into the first grand slam event of the year.

It was also the first time since 2008 that Almagro had been beaten before the third round at Melbourne Park.

They were joined in the second round by eighth-seeded Canadian Milos Raonic, who won 7-6 (7-3) 7-6 (7-3) 6-3 against Ukrainian qualifier Illya Marchenko.

Italian Fabio Fognini, the No.16 seed, was upset 4-6 6-2 6-3 6-4 by Colombian Alejandro Gonzalez.

Fellow Colombian Santiago Giraldo, the No.30 seed, belted Czech Jan Hernych 6-3 6-2 6-2 and American Steve Johnson eliminated British qualifier Kyle Edmund 6-4 6-4 6-3.