Victoria Azarenka is ready for some "top battles" as she bids to defend her Australian Open crown - starting with a tricky-looking quarter-final against Svetlana Kuznetsova.

Azarenka breezed through her last-16 encounter with Elena Vesnina today, winning 6-1 6-1 in 57 minutes - the latest in a series of mis-matches in the women's draw.

Meanwhile, Serena Williams trounced Maria Kirilenko, setting up an all-American quarter-final with Sloane Stephens.

Kuznetsova will be a different proposition for Azarenka. 

Having spent the last six months of 2012 recovering from knee surgery, the two-time major champion is now fit and looking good.

"I think it's going to be a very tough match," said top seed Azarenka.

"I can see Sveta has come back much fresher, much stronger.

"She knows how to handle big stages, big tournaments. She's a grand slam champion as well.

"It's definitely an exciting match for me to be in. I'm sure it's going to be really tough but I will give my best."

Azarenka was pleased to have made untroubled progress today after being embroiled in a three-set battle with American Jamie Hampton on Saturday.

World number 47 Vesnina was overpowered and overwhelmed on Rod Laver Arena with Azarenka returning to the kind of form which carried her to the title 12 months ago.

"I felt like I was playing pretty well today," she added.

"I was focused and in control from the beginning. That was important for me.

"I feel like I'm improving from match to match. I just want to keep going the same way.

"With every match you build up, the top battles are starting now and it's exciting to be this far in the tournament."

Kuznetsova, a former world number two whose lay-off has seen her drop to 75, came through a tough three-setter with former world number one Caroline Wozniacki, winning 6-2 2-6 7-5.

And she admitted she had even surprised herself in reaching the last eight.

"If you had asked me before coming to Australia...I would have laughed," she said.

"I have been working hard but still I have not had much time to work on my fitness."

Kuznetsova has won four of her seven meetings with Azarenka but lost both in 2012 and she knows she is facing a player who has developed over the past 12 months.

"She has got calmer, more consistent," she said. "She works differently and has different goals.

"I think her head was letting her down all the time before. She would always go crazy in matches. But she's changed and become more stable."

American Sloane Stephens (above) continued her impressive run in Melbourne by reaching her first grand slam quarter-final with a 6-1 3-6 7-5 defeat of Serbia's Bojana Jovanovski.

Serena Williams' win over Kirilenko sets up a quarter-final with her would-be successor Stephens.

The 31-year-old Williams needed less than an hour to advance under lights at Rod Laver Arena with a 6-2 6-0 victory, and will meet another woman in a hurry in teenager Stephens.

The wise-cracking 19-year-old has been touted as an heir to the 15-times grand slam champion Williams and bolstered her credentials with a mature 6-1 3-6 7-5 win over Serbia's Bojana Jovanovski in the afternoon sun at Hisense Arena.

But Williams fired a warning shot ahead of the generational battle, with her serve on fire and after bashing 22 winners against the 14th-seeded Russian.

"I think she's playing great," Williams said courtside of Stephens. "I think she has incredible talent, I actually admire her as well.

"I feel like I have nothing to lose and I'm just going to have fun when I play."