Nick Kyrgios has shot into outright favouritism to win the US Open after a thrilling victory over reigning champion Daniil Medvedev in New York on Monday afternoon.
The Aussie is through to the quarter-finals of the US Open for the first time after stunning the world with a 7-6 3-6 6-3 6-2 victory over the Russian.
Kyrgios now plays No 27 seed Karen Khachanov for a spot in the semifinals.
Aussie tennis great Todd Woodbridge said it was the best match he had ever seen Kyrgios play.
He called it a "momentous" victory that was more significant than all the wins he pulled off on his way to the Wimbledon final this year.
His fourth round blockbuster against Medvedev was expected to be one of the matches of the tournament — and it delivered in an avalanche of weird, wonderful and wild moments.
Kyrgios took the opening set 13-11 in a nail-biting tiebreak where he defended three set points.
However, the match was soon tied when Kyrgios came out in the second sluggish and timid.
Kyrgios appeared a different man in the third set and was grinning all over the court on his way to taking a 2-1 set lead.
It turned farcical in the third set when the 27-year-old had a moment of sheer madness and committed a foul shot in a moment that has stunned the tennis world.
At 30-30 in Medvedev's first service game of the set, Kyrgios had his opponent beaten after Medvedev's shot at the net popped up and was set to land out of the court near the chair umpire. Instead of letting the ball land on Medvedev's own side of the court, Kyrgios crossed to the other side of the net to cheekily put away a mock smash.
The chair umpire then took the point off Kyrgios as a result of a "foul shout".
It might have been funny for some sections of the crowd, but it cost him a break point opportunity.
The bizarre moment in the heat of battle left Aussie tennis great Todd Woodbridge staggered.
"I've never seen that in all my time in tennis," he said on Channel 9.
"Oh, what an error. That should have been a break point."
Earlier, Kyrgios produced some silky tennis just minutes after losing his cool in a tirade directed at the people sitting in his player's box, including doubles teammate Thanasi Kokkinakis and his girlfriend Costeen Hatzi.
"Tell me where to f***ing serve," he raged.
"F***ing three times. Say something. F***ing hell."
The outburst had American tennis commentators apologising to viewers.
"This place is so well mic'd that you're going to hear a lot of cursing tonight," one TV commentator said.