Serena Williams joins Venus in round four at Australian Open

Serena and Venus Williams showed their fighting qualities as both came back from a set down to reach the last 16 at the Australian Open in Melbourne.

Top seed Serena, 33, found her form to beat Ukraine's Elina Svitolina 4-6 6-2 6-0, while Venus, 34, saw off Italy's Camila Giorgi 4-6 7-6 (7-3) 6-1.

Four-time champion Novak Djokovic beat Fernando Verdasco 7-6 (10-8) 6-3 6-4.

Stan Wawrinka, the 2014 winner, defeated Jarkko Nieminen 6-4 6-2 6-4.

If younger sister Serena was expected to reach the fourth round and well beyond, the presence of Venus in the last 16 is a blast from the past.

The last time she went this far at a Grand Slam was at Wimbledon four years ago, and soon after she would be diagnosed with Sjogren's Syndrome, keeping her out of the sport for seven months.

"I do my best every single day," said the seven-time major champion, who faces sixth seed Agnieszka Radwanska next. "That's pretty much the way it goes. I think just not being afraid is the most important thing."

She added: "I like to win titles, whether it's a smaller event or a big event. That's what I play for. So, yes, it's great to be in the second week. But is the fourth round my goal when I come to these tournaments? No."

What's in a name? Two-time champion Victoria Azarenka seized the opportunity to correct her fans after a 6-4 6-4 defeat of Barbora Zahlavova Strycova.

"I love playing in front of you guys,'' Azarenka said with a smile into the microphone during her on-court interview.

"One thing I don't know is why everybody keeps calling me Vicky, but Vicky is not my name. It's Vika, Victoria, V, those are goers. Vicky is not my name.''

Whether it will be V for Victory again remains to be seen.

After blowing Fernando Verdasco's candles out, four-time champion Novak Djokovic was in playful mood.

The top seed was another to take the mic following his victory.

"Today is January 24, so I'd like you all to sing Happy Birthday to my mum," said the world number one.

The crowd duly obliged. No doubt Dijana Djokovic was delighted.

Feliciano Lopez is through to the last 16 after an impressive win over Jerzy Janowicz - one of the more straightforward episodes in the Spaniard's week.

Lopez beat Denis Kudla 10-8 in the fifth in round one, trailed by two sets when Frenchman Adrian Mannarino retired with heat exhaustion in round two, and in the same match struck a ballboy, external somewhere sensitive with a 124mph serve.

The 12th seed found himself posing for pictures with the watery-eyed youngster later in the day, and said: "It was very funny because he became very famous with his mates at school.

"Everybody was watching the video on YouTube. Thousands of viewers, I've heard. He was happy in a way, but he was also very fortunate when he was hit that he was OK after five, six minutes. He went out to sit down a little bit."

Jamie Murray continued his winning run at Melbourne Park with a first-round victory in the mixed doubles.

Playing with Taiwan's Hao-Ching Chan, the pair saved a match point as they beat Jarmila Gajdosova and Mahesh Bhupathi 6-4 6-7 (7-9) 10-8 in a court seven thriller.

Murray is also through to the last 16 of the men's doubles, where he and Australia's John Peers will face fourth seeds Ivan Dodig and Marcelo Melo.

In the junior singles, Bristol's Katie Swan beat New Zealander Jade Lewis 6-2 6-2 but Hertfordshire's Emily Arbuthnott lost 7-5 6-0 to Japan's Chihiro Muramatsu.

Eyebrows were raised when the schedule for Sunday was released, with Nick Kyrgios and Bernard Tomic absent from Rod Laver Arena once again.

Andy Murray and Grigor Dimitrov will play the men's night match, and Rafael Nadal versus Kevin Anderson the afternoon slot, leaving the Aussies on the second and third show courts.

"There are better matches on to be honest," Pat Cash told the The Age newspaper., external "Not from an Australian perspective, but from an international perspective.

"You can't not play Murray and Dimitrov on centre court, that's a pretty good line-up."

"I have a whole new appreciation for his game. He had great hands. I just saw he's amazing to watch. I really kind of liked that. But I was able to return his serve pretty well." Serena Williams enjoyed a recent exhibition doubles hit with Andy Murray.

"If you ask me right now after I ate a sandwich, probably six, four kilos. If you ask me first thing in the morning, probably six." A slim-line Milos Raonic on how much weight he has lost already this year.

"I didn't know I was coming to Australia until two weeks before I left, so just being here and being able to play, I'm so thankful." American Madison Brengle on reaching her first Grand Slam fourth round, two months after having a cancerous mole on her knee removed.

"Go for it. Roger?" Stan Wawrinka has a guess at what the media want to ask him about. Correctly.