ANDY Roddick believes a retro Roger Federer-Rafael Nadal Australian Open final would be more than a real-life fairytale.
"It might be, as far as history goes, the biggest match ever in Australian Open history - and maybe grand slam history," the former world No.1 said as the two tennis titans continued their march through the Melbourne Park draw.
"What's at stake there is beyond what pretty much what any player can comprehend."
Federer last night brushed aside Mischa Zverev in straight sets, 6-1, 7-5, 6-2, to book his semi-final berth against fellow Swiss star Stan Wawrinka, who crushed Jo-Wilfried Tsonga.
Nadal takes the next step to a potential Federer showdown tonight in a final-eight clash with Milos Raonic.
Grigor Dimitrov take on David Goffin in the other quarter-final today.
First up is the women's quarter-final clash between Mirjana Lucic-Baroni and Karloina Pliskova.