Nick Kyrgios goes nuclear in extraordinary defiance of umpire

Nick Kyrgios has reignited a running feud with a chair umpire at the Cincinnati Masters in one of the most explosive on-court tantrums of his career.

Having won the first set against Russian Karen Khachanov, things went pear-shaped for Kyrgios after he lost the second set tiebreaker.

Kyrgios complained of being unfairly treated "every single time" Murphy has officiated one of his matches.

The Aussie firebrand famously called the chair umpire a “potato” during a tournament in Washington and had another run-in with him at Queen’s earlier in the year.

In Cincinnati, the 24-year-old’s frustrations were clear to see after he was given a time violation on his serve.

Kyrgios snapped back by claiming that he would retire if Rafael Nadal played as fast as him.

His anger boiled over after Khachanov claimed the second set, with Kyrgios yelling his disapproval with the chair umpire in an expletive-laden outburst that left viewers gobsmacked.

He was duly slapped with a point penalty to start the deciding set.

Nick Kyrgios defied the chair umpire to smash two racquets off court. Pic: ESPN

The 24-year-old appeared to have calmed down somewhat when he asked if he could have a toilet break before the deciding set got underway.

Defiant Kyrgios goes on racquet-smashing rampage

The umpire appeared to deny the Aussie's request but Kyrgios walked off the court anyway.

Commentators questioned why he had taken two tennis racquets with him and the answer became clear moments later.

Walking off the court and inside the entrance to the locker rooms, Kyrgios could be seen through the door smashing both racquets into the ground, before turning and making his way back onto the side of the court.

Murphy looked bemused as Kyrgios came back with a destroyed racquet in each hand and radioed officials to see if they'd seen anything.

The answer came back negative despite the ESPN coverage clearly showing the incident - meaning Kyrgios was only hit with the solitary code violation.

Incredibly, the umpire then slapped Kyrgios with a time penalty moments later as the Aussie taped himself up a new racquet.

The Aussie was still raging as the third set went on but somehow managed to hold his first couple of service games.

However, things went downhill rapidly for the Aussie firebrand as he plummeted to a 7-6 6-7 2-6 defeat.

The unsavoury scenes ended with Kyrgios giving the umpire another mouthful, before spitting in disgust at what had just transpired.