PHOTOS: Djokovic, Murray, Sharapova advance with ease

World No 1 Novak Djokovic praised the battling spirit of Nicolas Mahut after he thrashed the injured Frenchman 6-0, 6-1, 6-1 in 74 minutes on Saturday to reach the Australian Open last 16.

Mahut, who was involved in an epic 11-hour match against John Isner at Wimbledon in 2010, turned 30 on Saturday and was battling with a left knee injury that severely restricted his movement in their third round match on Rod Laver Arena, something that Djokovic ruthlessly exploited.

Djokovic was relentless from the baseline, passing Mahut virtually at will and banging back deep service returns the Frenchman had no chance of returning with his movement hindered due to heavy strapping on his knee.

"Obviously I feel for my opponent, who evidently could not move on the court," Djokovic said. "He could not get over, you know, into the rally two, three strokes.

"I think most of the people expected him to just retire the match and walk out of the court," he added, mindful of the fact two previous matches on Rod Laver Arena had lasted little more than a total of two hours.

"But he managed to stay. So all the credit for him."

Djokovic used the blue hard courts at Melbourne Park to launch a spectacular 2011 when he won three Grand Slam titles and vaulted to the world's top ranking, but he said on Saturday he felt he was playing even better this year.

The Serb has barely been troubled in the first week of the year's first Grand Slam, conceding just 10 games in his three matches so far and he said that would only help as he moved into the second week and tougher matches.

"The positive out of this first week is obviously my performance has been great. I don't think that I need to work particularly in some shots of the game. Maybe just serve and maybe a little fitness, just get ready for the second week.

"I didn't spend that much time on the court. I don't think I'm lacking any match play. I don't think I'm lacking any practice. I've had lots of practice in the last five, six weeks.

"Right now I just want to take one match at a time, focus on the next one, and use this, well, physical, let's say freshness, that I have in this moment."

Mahut, who was presented with a cake by tournament organisers to celebrate his birthday, agreed that Djokovic was probably playing the best tennis of his life and would probably "come close" to the title again.

"I think a lot of people have trouble with Djokovic," he said. "I did my best but I played against the best player in the world.

Andy Murray enhanced his reputation as vanquisher of the French by moving into the fourth round of the Australian Open with a 6-4, 6-2, 6-0 demolition of Michael Llodra on Saturday.

The British fourth seed, losing finalist here for the last two years, secured his 25th victory in his last 26 matches against French players with an exquisite lob after 109 minutes on Hisense Arena.

Llodra, one of the last exponents of serve-volley, resembled a cavalry squadron charging a machine gun as he was repeatedly picked off by one of the most accurate players in the game.

Serena Williams raced into the last 16 of the Australian Open on Saturday with a powerhouse display that left Hungary's Greta Arn stunned after a 6-1, 6-1 drubbing on Rod Laver Arena.

The 13-times Grand Slam champion landed only half of her first serves but still cantered to victory in 59 minutes.

Arn produced same late resistance to prise a couple of break points from the American when trailing 4-1 in the second set, but surrendered the match meekly with a double-fault on the first of three match points.

Williams faces world number 56 Ekaterina Makarova in the fourth round after the Russian upset countryman and seventh seed Vera Zvonareva in straight sets.

Former champion Maria Sharapova continued to sweep through the Australian Open draw on Saturday with a dominant 6-1, 6-2 third round victory over German Angelique Kerber.

Kerber, the 30th seed, offered resistance to the aggressive Russian with a service break at 2-0 down in the second set but Sharapova simply upped the decibel level in her shrieks and battered her into submission in 87 minutes.

Showing no signs of the ankle injury that ruled her out of the Brisbane warm-up event, Sharapova, who won the last of her three Grand Slam titles in Melbourne in 2008, reached the last 16 having conceded just five games in three matches.

Second seed Petra Kvitova blasted into the fourth round of the Australian Open on Saturday when Russian Maria Kirilenko retired with a leg injury after the first game of the second set of their third round match, having lost the first 6-0.

Kvitova had torn through the first set in 34 minutes and then broke Kirilenko in the first game of the second before the 29th seeded Russian walked to the net and shook hands with the Czech.

Kvitova started slowly with the first game of the match taking 10 minutes before she broke Kirilenko and then ruthlessly exposed Kirilenko's hampered movement from the baseline.

Kirilenko took a timeout after going 5-0 down to have her upper left leg heavily strapped and, while she returned, Kvitova picked up where she left off.

Nicolas Mahut fell by the wayside but Jo-Wilfried Tsonga and Richard Gasquet kept the French fires burning by reaching the fourth round of the Australian Open on Saturday.

Six of the 15 Frenchmen to start the main draw made it to the third round at Melbourne Park with Tsonga, Gasquet and Mahut joined by Gael Monfils, Julien Benneteau and Michael Llodra.

With Gasquet and Tsonga winners over Janko Tipsarevic and Frederico Gil on Saturday, France need two more to advance to match the country's record of four in the last 16.

Tsonga took just 91 minutes to win 6-2, 6-2, 6-2 over Portugal's Gil, who had no answer to the Frenchman's power from the baseline. The World No 6 is a slow starter but hard to stop when he gets going.

"Every year and every tournament it's a bit of the same story for me," he said. "I play better and better every match.

"I played well and didn't spend a lot of time on court, and it's good for the rest of the tournament."

Gasquet, ranked 17th, had an even more impressive win over World No 9 Tipsarevic, dumping the Serb out of the tournament 6-3, 6-3, 6-1 on Margaret Court Arena.

"I hope we will go farther in the tournament," Gasquet said of the French contingent. "It's starting to be more and more difficult. We try our best to go further in the draw."

Argentine David Nalbandian has said he will appeal against an $8,000 fine after denying on his Twitter account on Saturday that he threw water at an Australian Open staff member.

The 30-year-old was fined for unsportsmanlike behaviour following Wednesday's heated second round match against American John Isner, in which Nalbandian argued with umpire Kader Nouni after the Frenchman overturned a point in the fifth set.

"To go ahead with this fine they are carrying out two injustices. One on and the other off the court. I'm going to appeal the fine," he wrote on his Twitter feed @nalbandiandavid.

"I strongly deny throwing water at an ATP assistant after the match against Isner.

"While he found me washing my hands during the anti-doping test, unbelievably the doctor in charge accused me of throwing water at him."

Nalbandian lost the marathon encounter and vented his fury on Nouni, who having overturned the point then refused to allow Nalbandian to challenge the call through Hawk-eye technology because he had taken too long to do so.

"It's ridiculous playing this kind of tournament with this kind of umpire. What did the ATP do this for?" Nalbandian told reporters after the match.