|Federer was in impressive form [EPA]
Roger Federer booked himself a quarter-final place in the Australian Open after shattering the hopes of local fans with a crushing 6-2, 6-3, 6-4 over Lleyton Hewitt in Melbourne.
The world number one's imperious display sets up an intruiging last eight showdown with Nikolay Davydenko, the in-form Russian who has won their last two meetings.
Davydenko, the sixth seed, came through a marathon five-setter against Spain's Fernando Verdasco, the ninth seed, prevailing 6-2, 7-5, 4-6, 6-7 (5/7), 6-3.
Looking ahead to the game, Federer said: "I'm in for a good match for sure. I favour my chances in a best-of-five set match. We'll see how it goes."
Paying tribute to Hewitt, the 15-time Grand Slam champion said: "I have always had some great battles with Lleyton, he's a champion and has the ability to make you nervous in a match."
Third seed Novak Djokovic, the 2008 winner, also progressed with an emphatic 6-1, 6-2, 7-5 win over Poland's unseeded Lukasz Kubot and will next meet French 10th seed Jo-Wilfried Tsonga, who he beat in the 2008 final.
Djokovic struggled in the opening two rounds of the competition, but has moved up a gear and is back with the touch he displayed in the second half of last year.
"I think the first two sets I was very dominant on the court, then he lifted up his level of the game a little bit," he said.
"In general, I was very happy with the way I performed today."
Tsonga won a thriller against Nicolas Almagro, the Spanish 26th seed, 6-3, 6-4, 4-6, 6-7 (6/8), 9-7.
The 24-year-old, who had never played a five-set match in a Grand Slam before, said: "It was good. Good to win in five sets, first time for me."
Spanish defending champion Rafael Nadal, British fifth seed Andy Murray, American seventh seed Andy Roddick and 14th seeded Croat Marin Cilic make up the rest of the draw in the quarters.
In the women's competition, the Williams sisters, Venus and Serena, also progressed to the quarter-finals, while Li Na ensured China will have two players in a Grand Slam last eight for the first time.
Like Federer, women's defending champion Serena, who is gunning for a fifth Australian title, was a class apart as she devoured Australia's Sam Stosur 6-4, 6-2.
She will play seventh seed Victoria Azarenka after the Belarussian beat ninth seeded Russian Vera Zvonareva 4-6, 6-4, 6-0.
Serena said: "It's really good to match my game against her [Stosur's] serve, because she's one of the best servers on the tour.
"It's important when you're playing a local girl to not let the crowd get too involved or else they'll kill you. That was the plan, to not let them get involved."
Venus, Serena's sister and seeded six, found the going tougher against Italian 17th seed Francesca Schiavone, losing the first set before bouncing back for a 3-6, 6-2, 6-1 win.
They join Li, Justine Henin, Nadia Petrova, Maria Kirilenko and Zheng Jie in the last eight.
Venus is in her 11th Australian Open campaign but is yet to win the singles crown, in stark contrast to Serena.
But the elder Williams is not beating herself up about her comparative lack of success, insisting a major part of her game plan was staying positive.
"Yeah, I'm ready to go and I feel very good," said Venus, who has won five Wimbledons and two US Open titles.
She faces Li next after the 16th seed upset Danish fourth seed Caroline Wozniacki 6-4, 6-3.
Li's victory broke new ground for Chinese tennis, with the 27-year-old joining compatriot Zheng in the last eight, the first time two Chinese players have reached that stage of a Grand Slam.
Li is looking forward to meeting Venus, who she beat in their only previous match at the 2008 Beijing Olympics.
"It was a good experience for me, for my tennis," she said of the Olympic win. "But I just want to forget because I play her again. I want to look forward."