German journeyman Florian Mayer has advanced to the fourth round of the Australian Open for the first time in 10 attempts with a surprise straight-sets victory over Wimbledon semi-finalist Jerzy Janowicz.

The 30-year-old Mayer won 7-5 6-2 6-2 against Janowicz, the No.20 seed from Poland.

Janowicz had been lucky to get through the opening round, where he had to come back from a two-set deficit against impressive Australian wildcard Jordan Thompson.

Mayer will play No.3 seed David Ferrer from Spain or Frenchman Jeremy Chardy in the round of 16.

Janowicz said he had yet to fully recover from a broken foot, which had prevented him practising for two months.

“My problem today was that I was unprepared and I had played two matches in a row that went for over three hours,” he said.

“In the second round, it was three hours and 30 minutes and it was extremely hot, over 41 degrees and I was really exhausted for this match.

“Because I didn’t practise much, I was not able to get ready for the next match.

“Today I was completely kaput.”

Janowicz missed last year’s Davis Cup World Group playoff loss to Australia due to a back injury.