NEW YORK, NY - SEPTEMBER 03: Roger Federer of Switzerland congratulates opponant John Milman of Australia following their men's singles fourth round match on Day Eight of the 2018 US Open at the USTA Billie Jean King National Tennis Center on September 3, 2018 in the Flushing neighborhood of the Queens borough of New York City. (Photo by Alex Pantling/Getty Images)

Australian John Millman has told shocked the tennis world by defeating Roger Federer in four sets to earn a place in the US Open Quarterfinals.

The 29-year-old came up against the world number two seed in the Fourth Round of the last grand slam for 2018, with Federer going into the match as the red hot favourite to make the final eight.

After Federer discarded fellow Aussie Nick Kyrgios in three straight sets during the third round, experts and fans alike felt Millman was no threat to the Swiss champ.

But, they were wrong.

The game started off as everyone expected with Federer quickly racing to claim the first set 6-3, before the Aussie hit his strides to then take the next three sets to prevail over the champ in four.

Recording a 3-6, 7-5, 7-6, 7-6 win over Federer means Millman will now face Novak Djokovic in the quarterfinals.

Millman's stunning victory has denied the die-hard tennis fanatics of a Federer v Djokovic quarterfinal, where the two champions have won seven US Open titles between them.

After the historic win, Millman could barely contain his emotions, showing incredible respect and sportsmanship for his opponent during his post-match on-court interview.

“I have so much respect for Roger, he is a hero of mine...Today he wasn't at his best but I'll take it,” Millman said.

"I felt like a little bit of a deer within the headlights to start with, my toes weren't transferring. Roger had it on a string, he was manipulating me across the courtroom.

"However I received out of a troublesome second set and actually discovered my feed, determined to be a bit of bit extra aggressive. I feel I actually discovered my serve. I feel I served very well. I in all probability capitalised on Roger having an off service day."

This is the Brisbane-based player's first win against an opponent ranked in the top 10, as he now turns his attention to the sixth seeded Serbian.

The out-pour of support from the Australian public has come thick and fast through twitter, with many offering their congratulations to the 55th ATP ranked seed:

Millman's quarter final clash with Djokovic will take place on Thursday September 6, with the broadcast time for Australia yet to be announced.