Nick Kyrgios has crashed out of the US Open in a first round match during which he appeared to be more preoccupied with the toilet break controversy from Stefanos Tsitsipas' win earlier in the day.

The Australian firebrand never looked in the contest against Roberto Bautista Agut, falling 6-3, 6-4, 6-0.

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Kyrgios appeared frustrated throughout the match, arguing with the chair umpire and his own box as he fumed over toilet breaks and towels throughout the first round loss.

The 26-year-old had already chided Tsitsipas in the comments of an Instagram post from the official US Open account over the toilet break controversy, which left first round opponent Andy Murray apoplectic.

It was Kyrgios' turn to fire up after the second set when Bautista Agut took a brief toilet break of his own.

Already complaining about having to play at 11pm in New York, Kyrgios was docked a serve for repeated time violations in the third set.

Not that it would matter, as it was already clear by this stage that Kyrgios wanted to match to be done sooner rather than later.

Kyrgios fell into a foul mood early, bickering with the chair umpire about having to walk his towel to the corners of the court instead of throwing it where he wanted.

“My job is to come out here and play for the people, not walk back and forth between towels,” Kyrgios said.

“It’s not part of the game. So texting someone’s part of the game too? Taking a 20-minute bathroom breaks is part of the game? I need to take a s**t, part of the game.”

As part of the ATP and WTA tour's coronavirus prevention protocols, ball boys and girls are prohibited from touching players' towels.

Needless to say, Kyrgios' antics were not well received by tennis fans, who viewed his latest effort as more evidence against his place on the tour.

Having openly admitted to lacking motivation across several tournaments leading in to the US Open, the loss to the Spaniard consigned Kyrgios to the worst losing streak of his career.

His fourth consecutive loss was also one of the worst of his career, winning the fewest games of any match he had played in a grand slam, not including injuries and retirements.

Kyrgios also turned his frustrations towards his own box, saying partner Chiara Passari and another member of his team were 'the only two idiots wearing a mask'.

Tsitsipas US Open 'nonsense' annoys Murray

Andy Murray says he has lost respect for Stefanos Tsitsipas after bowing out of the US Open to the world No.3 in a dramatic and at times ill-tempered near five-hour five-setter.

The 34-year-old Scot was livid at the lengthy bathroom breaks Tsitsipas took between sets and demanded more should be done to clamp down on the "nonsense".

"It's not so much leaving the court. It's the amount of time," Murray said after his 2-6 6-7 (7-9) 3-6 6-3 6-4 first-round defeat.

"I spoke to my team before the match about it and said to expect that, prepare for it if things were not going his way.

"So I was trying to do that but the issue is that you cannot stop the way that that affects you physically. When you're playing a brutal match like that, you know, stopping for seven, eight minutes, you do cool down.

"It's just disappointing because I feel it influenced the outcome of the match. I rate him a lot. I think he's a brilliant player. I think he's great for the game.

"But I have zero time for that stuff at all, and I lost respect for him. That's what I feel.

"But if everyone else feels like that's totally cool and there's no issue with it, then maybe I'm the one being unreasonable.

"But I think it's nonsense. And he knows it, as well."

Murray came so close to the biggest win of his comeback from career-saving hip surgery, almost defying the odds, the heat and a slippery pair of shoes as well as the borderline gamesmanship from the 23-year-old Tsitsipas.

Having won the first set - the first he had taken from a top-five player since 2017 - Murray had two points to clinch the second in the tiebreaker.

But drenched in sweat in the humid conditions, he began complaining that his trainers had become too slippery - yet it soon became apparent he did not have a spare pair.

With AAP