Lleyton Hewitt could only marvel at the brilliance of Roger Federer after the world No.1 handed Australia's court warrior his worst-ever Australian Open loss on Monday night.

Federer stunned the capacity crowd at Rod Laver Arena with a sublime display, destroying Hewitt 6-2 6-3 6-4 in one hour, 55 minutes to move majestically into his 23rd successive grand slam quarter-final.

"It's always disappointing when you lose in a grand slam, but he played special tennis," Hewitt said.

"He hit the ball extremely clean and I just couldn't get into his service games, which made it tough.

"He was confident and moving extremely well. I felt like he was putting the ball on a dime every time."

Federer's 15th straight victory over Hewitt, a remarkable streak stretching back to the South Australian's famous five-set Davis Cup triumph over the Swiss maestro at Melbourne Park in 2003, completed a dreadful night for the locals.

Women's world No.1 Serena Williams earlier brought Samantha Stosur's Open to an equally abrupt end with a 6-4 6-2 fourth-round demolition job.

Having lost seven of his first nine career encounters with Hewitt, the ever-respectful Federer admitted his former doubles partner now brought the best out in him.

"It used to not be the case," Federer said. "But we had some really good matches back when I lost, too, you know.

"But I always think they're extremely tough, physically and mentally very challenging. You know you're going to be caught up in quite a tough match always against him.

"Even though the scoreline (shows) something else tonight, I had to really dig deep and come up with some amazing shots to beat him."

Hewitt entered his eagerly-awaited match with high hopes after reaching the last 16 without dropping a set and having pushed Federer to four tight sets in their most recent meeting at the US Open last September.

But lacking the firepower and class of Federer, Australia's former world No.1 must have realised quickly he was up against it.

"There's nothing he can do," said respected coach Brad Gilbert, commentating on ESPN, as the 15-times grand slam champion continually painted the lines in the two-hour mismatch.

Despite his defeat, Hewitt will return to the top 20 after the Open and remains confident that better days lay ahead in 2010.

"Obviously I've been able to work my ranking back up. I feel good about that," he said.

"I don't have a lot of points to defend really through to Wimbledon, the quarters there.

"So I feel comfortable I can do some damage. The way I hit the ball tonight, I still think I could have taken a lot of other guys still left in the draw. That's probably a little bit more frustrating."

Hewitt started positively enough, matching Federer's two aces in his opening service game and then holding to love for 2-2.

But the 2005 runner-up had to scrap for every point from then on.

The pressure told in the sixth game when Hewitt gifted Federer the first break of the match with four lame unforced errors.

The top seed held to love for 5-2 and then drilled a crosscourt forehand to break Hewitt again to pocket the opening set in 32 minutes.

It was more of the same in the second set, with Federer smoking a backhand down the line to break Hewitt and charge to a 4-1 lead, and the set was as good as over.

Typically, Hewitt put up a fight in the third set, breaking Federer back for 4-4 after dropping his serve for a fourth time in the seventh game.

But Federer broke back immediately with another beautiful crosscourt forehand pass before finally putting Hewitt out of his misery the next game to book a quarter-final date with in-form Russian Nikolay Davydenko.

The victory extended Federer's flawless record over Hewitt in grand slam encounters to 8-0.