Murphy eventually responded by handing Kyrgios a point violation after Khachanov won the second set tiebreaker to level the match,when the 2014 Wimbledon quarter-finalist over-stepped the mark by screaming out an obscenity.
Kyrgios then followed this up by asking for a toilet break. He took two racquets with him and smashed them in the players'tunnel before returning to the court.
Kyrgios'behaviour was not lost on the TV commentators,with former British player Barry Cowan saying:"We’re not going to hear the end of this."
"What he did at the end,quite frankly,was disgusting,"Cowan said.
"I personally don’t like not shaking hands but ... it looked like he did spit in his direction
"He said he was turning a corner,but tonight was a step back unfortunately."
Kyrgios is poised to return to seedings territory at the majors when the US Open begins in New York on Monday week.
Australia will have at least 10 players in the women's and men's singles main draw.
Kyrgios,Alex de Minaur,Jordan Thompson,2018 quarter-finalist John Millman and emerging teenage star Alexei Popyrin will contest the men's event.
French Open champion Ashleigh Barty will headline Australia's women's contingent.
Another 16 Australians have entered US Open qualifying - eight men and eight women.
Bernard Tomic has pulled out of US Open qualifying but still hopes to contest the final grand slam of the year.
Scott Spits,with AAP