Australian tennis player Alexei Popyrin has just knocked Novak Djokovic out of the US Open in a clinical performance.

Claiming the first two sets without bring broken, Popyrin took home the third round clash with a scoreline of 6-4, 6-4, 2-6 and 6-4 in his greatest win on the tour.

Played in prime-time across the United States, Popyrin de-throned the 24-time major champion in three hours and 18 minutes.

Overwhelmed with emotion, Popyrin let himself go in the post-match celebrations as the local crowd embraced the achievement from the Aussie star.

Popyrin joins mentor Lleyton Hewitt as the only two Australians to beat Djokovic in a grand slam match.

Speaking after the match, the 25-year-old says he took great experience from the last time he faced Djokovic in grand slam tennis.

“We had some battles at Wimbledon and the Australian Open – I had my chances in those matches and didn’t take them,” Popyrin said post match,” Popyrin said.

“This match was a little different. I was able to take my chances when I had them.

“It’s unbelievable because I’ve been in the third round about 15 times but I haven’t been able to get past that point – to do so against the greatest player of all time to get into the fourth round is unbelievable.”