Defending champion Victoria Azarenka set up an Australian Open rematch against Sloane Stephens with a thumping win over Yvonne Meusburger in the third round.

Azarenka, the winner of the title the last two years, took exactly an hour to defeat Austrian Meusburger 6-1 6-0, winning the final 11 games.

But, as impressive as Azarenka was, it is the pairing of the Belarusian with Stephens 12 months after their controversial semi-final encounter at Melbourne Park that will make the headlines.

Stephens, then a teenager, was playing in her first grand slam semi-final and had just saved five match points to get the second set back on serve.

Azarenka chose that moment to take a long medical time-out before breaking the Stephens serve to clinch victory.

In her on-court interview after the match, Azarenka joked she had nearly committed "the choke of the year", implying the break was tactical.

She later insisted she had been misunderstood and in fact had been struggling with a locked rib that made it difficult for her to breathe.

The pair, who share an agent, have not met since and, asked in her press conference after beating Elina Svitolina on Saturday what their relationship was like, Stephens replied: "Non-existent."

Azarenka went on to win the final against Li Na last year despite the crowd heavily supporting the Chinese player 

Stephens made sure of her passage to the fourth round of a fifth straight grand slam after beating Elina Svitolina 7-5 6-4.

Elsewhere Caroline Wozniacki was beaten 4-6 7-5 6-3 by fast-improving young Spaniard Garbine Muguruza in the third round.

It meant that for an eighth successive slam Wozniacki has gone out before the quarter-finals, and she has reached the second week just once in that time.

Wozniacki led in the second set, and she said: "Sometimes it happens, you just don't take your chances.

"I don't think I did anything particularly wrong. I thought she played some great tennis as well. It was just a bit unlucky."

Maria Sharapova needed almost three and a half hours to see off Karin Knapp in extreme heat on Thursday, and she wobbled in the second set against Alize Cornet on Saturday before pulling through 6-1 7-6 (8/6).

The third seed was so unhappy with her lack of rhythm that she hit the practice courts straight after her match.

Sharapova said: "Everyone that played a long match in those conditions (on Thursday) is going to feel physically and emotionally tired, and that's the way it goes.

"You just have to find a way to get through it. That's what I did. It was quite tough in the end. She had a set point and she had a chance to level the match, which is something I probably wouldn't want to do, go into a third set.

"I was happy I was able to finish it in two."

Sharapova missed the last three months of 2013 with a shoulder problem, and she added: "I still feel like in certain situations I am a bit rusty and I'm not closing it out when I have to or maybe going for a little much or over-thinking it a bit.

"That will come. I'm not worried about that. As long as I feel like I'm doing the right things and I'm playing the way I want to play, if I'm making those types of errors, they are going to go in eventually."

Sharapova next plays 20th seed Dominika Cibulkova, who benefited from Carla Suarez Navarro's exhaustion after an epic match in the heat on Thursday to win 6-1 6-0.

Agnieszka Radwanska, who has been making hard work of her draw came through another three-set match against Anastasia Pavlyuchenkova.

Eighth seed Jelena Jankovic and 11th seed Simona Halep were also straight-sets winners and will play each other in the last 16.