US Open: Nick Kyrgios fined again for using obscenity

Nick Kyrgios celebrates during his match against Daniil Medvedev. Photo / AP

Nick Kyrgios has been fined again as the US Open took issue with his behaviour during his massive victory over Daniil Medvedev on Monday.

The 27-year-old put on a masterclass to defeat the reigning champion in New York in a victory described by Aussie great Todd Woodbridge as Kyrgios' "best ever" win.

However, in a cold development to his performance, the US Open announced overnight Kyrgios has been fined a further $4000 for an "audible obscenity".

It is the third time he has been fined by the tournament. He was also hit with the biggest fine of the tournament, $7500, for "spitting and audible obscenities" during his second-round victory at Flushing Meadows.

He was also fined $4000 for racquet abuse during a doubles match with Thanasi Kokkinakis.

His latest $4000 fine means he has coughed up US$15,500 ($25,600).

The fine came after Kyrgios was heard on court microphones repeatedly swearing at his player's box.

His tirades towards his entourage, which includes girlfriend Costeen Hatzi, have become a bizarre tactic he routineley uses to pump himself up in matches.

It has made things very awkward for his team in New York.

Kyrgios produced some silky tennis just minutes after losing his cool early in the match against Medvedev.

"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.

"Sorry about that."

Earlier in the tournament, Kyrgios was seen in an incredible rant where he complained to the chair umpire that he could smell marijuana smoke coming from the crowd.

"It was f***ing marajiuana," he yelled.

"It was smoke. Obviously I'm not going to complain about food.

"Obviously when athletes are running side to side and they have asthma, it's probably not ideal."

Minutes before his argument with the chair umpire, Kyrgios had again barked at his player's box.

"Go home if you're not going to f***ing support me bro," he shouted.

Kyrgios has shot into outright favouritism to win the US Open after the thrilling victory over Medvedev.

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.

In a golden, memorable, night for Australian tennis, Aussie star Ajla Tomljanovic also moved through to the quarter-finals with an ultra-impressive victory over Ludmilla Samsonova.

Kyrgios has been scheduled as the second match during the night session on Arthur Ashe Stadium on Wednesday morning. (AEST).