The question seemed to be a compliment. Sure, Novak Djokovic's run of dominance in recent times has been impressive. But did the Serb star have to overcome the same calibre of player that Federer faced throughout the mid-2000s, when the Swiss maestro was revered as the world's best player?

It's a question worth pondering, but not one that Federer seemed interested in investing in after he succumbed in four sets to Djokovic in the semi-final of the Australian Open.

"You've got to be careful how to phrase the question," Federer, 34, said after a few seconds of silence.