Two-time defending champion Roger Federer fell at the Australian Open and Stefanos Tsitsipas rose like a Greek god to advance to the quarter-final in four sets.

Inside Rod Laver Arena on Sunday, January 20, there was one very defining moment where the proverbial torch was passed – as Roger Federer's backhand crashed into the net, Stefanos Tsitsipas stood with jaw dropped, mouth wide open and with a tear trickling down from his left eye looked at his box. He pointed towards himself and gestured, 'Is it me?'

Yes, it was him and how! The Greek was almost unplayable for most of the night, not just dominating but overpowering Federer with his heavy forehands; and when he was not unplayable, he was gritty – chasing down every drop shot from behind the baseline and saving as many as 12 break points.

Stefanos Tsitsipas
Tsitsipas could not believe he had defeated Roger Federer.Darrian Traynor/Getty Images

When it was all said and done and the crowd stood up to acknowledge the legend of Federer goodbye, Tsitsipas stood on his bench staring wide-eyed at the scoreboard that read 6-7, 7-6, 7-5, 7-6.

"I'm the happiest man on earth right now, I can't describe it," Tsitsipas said after the match. Tsitsipas was clearly dazed and in a state of disbelief in the post-match interview when he spoke about Federer has been his idol since he was six years old. The 20-year-old was only 6 weeks and 6 days old when the Swiss played his first ATP match.

Stefanos Tsitsipas
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With this victory, the 13th seed added Federer to his list of defeated opponents that includes Novak Djokovic, Alexander Zverev, Dominic Thiem and Kevin Anderson. 

Federer admitted that he lost to a better opponent in his post-match press conference saying, "I lost to a better player who played very well. He stayed calm and hung in there, which is not easy for younger guys so credit to him."

The most telling aspect of the Greek's game was the resurfacing of the lost art of net play. Tsitsipas made 68 forays towards the net and won 71 per cent of these points. 

Stefanos Tsitsipas
The Greek reined supreme in Melbourne.Darrian Traynor/Getty Images

"I believe coming into the net and being aggressive and taking the ball early, we have to keep it going," he said. "Most players in this era are baseliners. I like this aggressive game, coming into the net, and serve and volleying now again. It keeps the game alive and makes it much more interesting."

A 6'4' 20-year-old with a fierce serve; an appetite for rushing to the net; a will to chase down every shot and the grit to fight out of difficult corners, Melbourne Park may have witnessed the rise of a modern great.