Former world No 1 Jim Courier likens Roger Federer's Australian Open draw to being "on murderer's row".

To land a record fifth Open crown, Federer must beat Wimbledon champion Andy Murray tonight and then, in all likelihood, world No1 Rafael Nadal in the semi-finals and three-time defending champion Novak Djokovic in the title match.

"If that would happen, it would be extraordinary," doubles great Todd Woodbridge said.

Record keepers suspect it would be unprecedented. They can never recall any man conquering three reigning grand slam champions to win a major.

But never before had any man won 17 grand slam singles titles either before Federer came along and rewrote the record books.

And after his virtuoso display against Jo-Wilfried Tsonga in the fourth round, Federer - hitting it flatter and faster with his new oversized racquet and thriving under new coach Stefan Edberg - refuses to rule it out.

"If you don't embrace that challenge, you might as well not enter the draw," he said. "You might as well stay at home and watch other guys battle it out."

But he acknowledges it won't be easy.

"It's a tough thing to do," Federer said. "Clearly you need to change your game depending on the players because Murray plays different to Djokovic, Djokovic plays different to Rafa, and Jo and so forth.

"You are always also a bit dependent on how good their form is, how good is yours.

"Can you do it three or four times in a row? It's definitely a tough task."

Federer's immediate concern is finding a way past Murray in their first clash since the Scot edged the Swiss in five sets in last year's semi-finals.

After early exits at Wimbledon and the US Open last year, Federer says his sublime form against Tsonga removed any lingering doubts he remained capable of challenging the Murrays, Djokovics and Nadals, the sport's new big three.

"I know I'm going definitely in the right direction," he beamed.

Should Federer pull off the improbable and down Murray, Nadal and Djokovic in successive matches to capture an 18th grand slam title at 32, Woodbridge would rate it possibly his greatest triumph.

"It would definitely rate as one of his best because where he's come from," he said.

"Against Tsonga, he came out and played probably the best match he's played in two years, not just his ball striking but tactically he played as smart as he has for a long time.

"So the conversations about tennis between he and Edberg must be resonating with him. There's something fresh that he's taken on." AAP