Young Greek star Stefanos Tsitsipas had done his homework on Roger Federer

The 20 year old stunned the defending champion in an epic four setter on Rod Laver Arena to reach his first Grand Slam quarter final.

Tsitsipas says he has been studying Federer since he was six years old and heading into this match had watched several You Tube videos of Federer defeats.

He says he watched some highlights of players that beat him in Grand Slams, especially at the US Open.

Fourth round action continues this afternoon from one o'clock with Ukraine's Elina Svitolina up against American Madison Keys.

TENNIS WITH CROWN FORKLIFTS. WHEN IT COMES TO FORKLIFTS, THERE'S NOTHING LIKE A CROWN.