Australian Open: Roger Federer joins Rafa Nadal and Andy Murray in the last 16

(CNN) -- The heat was off Roger Federer as he joined fellow grand slam winners Rafael Nadal and Andy Murray in the final 16 at the Australian Open.

Federer zipped through a 6-2 6-2 6-3 win over unseeded Russian Teymuraz Gabashvili as the searing temperatures eased in Melbourne and distinctly grayer skies loomed over the show courts.

The 32-year-old is chasing a fifth title in Australia and an 18th career grand slam but for now Federer is grateful for small mercies after a niggling back injury saw him lose form in 2013."I'm just happy waking up in the morning and not feeling like an old man," he told reporters. "So that's very positive. Right now I feel very fresh and very good physically."My first goal was to get through the first week, now clearly the draw is very difficult. I've done the work, I've not lost a set so far, so we'll see how it goes."

It's a French test for Federer next as he faces Jo-Wilfried Tsonga, the 10th seed, for a place in the quarterfinals.

If he advances to the final eight, Federer would face Murray -- the man who beat him in an absorbing Australian semifinal last season.

Murray, the Wimbledon champion, battled through a first set tiebreak to see off Spain's Feliciano Lopez for his place in the last 16, where he faces unseeded Frenchman Stephane Robert.Confident was the word Nadal ominously used to describe how he was feeling after he breezed through with a 6-1 6-2 6-3 win over Gael Monfils.

"Well today I think I have to say that I played well from everywhere, no?" the Spanish world No. 1 teased reporters after his match in Melbourne.

In the women's draw, defending champion Victoria Azarenka lost just one game as she whizzed into the fourth round in Melbourne.

There she will face American Sloane Stephens in a rematch of last year's semifinal when Azarenka caused a stir by taking a medical timeout just as Stephens appeared to have the upper hand in the second set.

"We left it all here last year," said Azarenka, when asked if she had spoken to Stephens about the incident. "That's what is important for me, to play another match. I'm looking forward to it."

Russian third seed Maria Sharapova hit her way through a tight second set to see off France's Alize Cornet 6-1 7-6 while fifth seedAgnieszka Radwanska and Jelena Jankovic also advanced.

But there was disappointment for Danish 10th seed Caroline Wozniacki as she lost 6-4 5-7 3-6 to unseeded Spaniard Garbine Muguruza.

Wozniacki, who is engaged to golfer Rory McIlroy, said she now intends to zone out from the Australian Open -- although she said it politely of course."When I'm not in the tournament anymore, it sounds rude, but I don't really look at the games anymore," she explained.