Australian world number 30 Nick Kyrgios fought back to beat Pierre-Hughes Herbert at the US Open after an apparent pep talk from the umpire.

Kyrgios was a set and 0-3 down to his French opponent when official Mohamed Lahyani climbed down from his chair during a changeover.

“I want to help you. This isn’t you. I know that,” Lahyani said.

Krygios went on to win 4-6 7-6 (8-6) 6-3 6-0 and could play world number two Roger Federer next.

Swiss Federer, a five-time champion at Flushing Meadows, is playing France’s Benoit Paire for a place in the last 32.

Kyrgios claimed after the match that Lahyani was concerned about his medical well-being rather than his motivation in their on-court discussion.

“He was just concerned about how I was playing – he was like: ‘Nick are you OK?'” said Kyrgios.

“I was like: ‘Yeah everything is fine.’ I just wasn’t feeling great.”

The 23-year-old won 19 of 25 games after the exchange and the incident sparked debate online.

Kyrgios, who hit 25 aces in his first-round win over Radu Albot, delivered the joint-fastest serve of the tournament so far with one 142mph tee-off.

Elsewhere world number four Alexander Zverev advanced to the third round for the first time with a comprehensive win over France’s Nicolas Mahut.

The 21-year-old German won 6-4 6-4 6-2.

Fourteenth seed Fabio Fognini fell victim to Australian John Millman, losing 6-1 4-6 6-4 6-1.

Andy Murray joked he need a check-up as he has “started imagining things” after Fernando Verdasco denied he had spoken to his coach during the heat break in their US Open second-round tie.

Players are not allowed to be coached during breaks for extreme heat.

Murray reported Verdasco, who won in four sets, but the Spaniard said: “I don’t want to say that Andy lied but I didn’t talk one word with my coach.”

Murray later posted a response using the hashtag #liarliarpantsonfire.

Writing on Instagram, Murray thanked fans for their support and joked: “I’m off to get a health check as apparently I’ve started imagining things.”

• It’s normal to have doubts over my tennis future – Murray
• Murray beaten in US Open second round

Earlier, following his 7-5 2-6 6-4 6-4 defeat, Murray had said Verdasco and his coaching team “probably weren’t aware of the rule” about heat breaks.

“When I came out of the shower, his coach and one of the Spanish doubles players were in there chatting to him, and you’re not allowed to speak to your coach,” said Murray.

“I’m not blaming Fernando and his team. They certainly weren’t trying to break any rules.

“It shouldn’t be for the player that’s competing against him to have to go to the supervisor.”

Both players left the Arthur Ashe court at the end of the third set after Spaniard Verdasco took up the 10-minute extreme heat break with temperatures rising close to 100F (38C).

However, the 34-year-old denied Murray’s claim, saying his coach was only in the locker room to go to the toilet.

“I was in the ice bath with Marcos Baghdatis and his coach,” Verdasco said.

“I know exactly the rule and I don’t want to be the one breaking it.”

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Andy Murray says it is “completely normal” to have doubts about whether he can return to the top of the game after his Grand Slam return ended in a second-round defeat at the US Open.

The British former world number one lost in four sets to Spanish 31st seed Fernando Verdasco at Flushing Meadows.

Murray, 31, was playing best-of-five matches for the first time since hip surgery in January.

“You just don’t know exactly what’s round the corner,” he said.

Murray, a three-time Grand Slam champion, has only played five tournaments since returning to the ATP Tour in June after an 11-month absence with the hip problem.

• Murray beaten in US Open second round
• ‘Liar, liar, pants on fire’ – Murray responds after Verdasco denies coaching claim

Now ranked 382nd in the world, Murray said he played some of the best tennis of his comeback against Verdasco, but also lamented making mistakes and admitted it “wasn’t the most comfortable” he had felt on court.

“When I got the injury, I was ranked number one in the world, 12 months later things completely changed,” he said.

“If things keep going smoothly, physically I continue to improve, I believe that I will get back to competing for the biggest competitions because there’s no reason why I couldn’t.

“When you continue to build up and start playing more tournaments, you don’t know how you’re going to respond.

“Because of the path that I’ve been on the last year with the many ups and downs, trying to come back, it not quite working, then ending up having the surgery, I think it’s completely normal to have those doubts.”

Murray eyes Davis Cup return

Murray says he would “love” to play in Great Britain’s Davis Cup tie against Uzbekistan in Glasgow next month.

But the Scot says he needs time to assess his fitness after his US Open exit.

“Potentially it’s the last time I’d get to play competitive tennis in Scotland so I’d like to do that,” he said.

“I’d have to chat to my team because this is obviously a very important period in my rehab and my long-term strategy.”

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Murray has long carried the flag for British tennis and helped his nation win the Davis Cup for the first time in 79 years when they beat Belgium in 2015.

He has not played in the competition since Britain suffered a semi-final defeat by Argentina in September 2016, missing three matches since through a combination of fatigue and injuries.

After returning to competitive action in June, he pulled out of Wimbledon before making his Slam return at Flushing Meadows on Monday.

An opening win against Australia’s James Duckworth was followed by defeat against Verdasco on Wednesday.

“Playing five sets takes a lot out of you, which I’ve obviously learned in the last couple of days, and the Davis Cup has also taken a lot out of me,” he said.

“But there’s a big part of me that would love to play and get the opportunity to play one last time in Glasgow.”

The controversial revamp of the Davis Cup, which comes into effect in 2019, means there will only be one home or away tie each year before a season-ending final held in a neutral venue.

Andy Murray’s return to Grand Slam tennis ended in a four-set defeat by Spanish 31st seed Fernando Verdasco in the US Open second round.

The former British number one, playing his first Slam in 14 months, lost 7-5 2-6 6-4 6-4 in New York.

In sweltering conditions, Murray, 31, battled hard but did not have enough to overcome the 34-year-old Verdasco.

Compatriot Cameron Norrie lost 6-2 2-6 6-4 6-4 to Serbia’s Dusan Lajovic as British singles representation ended.

• It’s normal to have doubts over my tennis future – Murray
• ‘Liar, liar, pants on fire’ – Murray responds after Verdasco denies coaching claim

It was only Murray’s fifth tournament back since having hip surgery in January.

The Scot looked exhausted at times during a physical encounter on a humid Arthur Ashe Stadium – a combination of the conditions as temperatures rose close to 100F (38C) and his lack of five-set matches since being sidelined through injury.

Murray’s limp between points – a regular sight in recent years – seemed to become heavier as the match wore on.

“It wasn’t the most comfortable I felt on a tennis court. I got through it and fought right to the end,” he said.

Murray continued to show the dogged determination that helped him win three Grand Slam titles at the peak of his powers, pushing Verdasco to the limit before succumbing to a third match point in three hours and 23 minutes.

Despite defeat, Murray felt he played some of his best tennis since returning to the ATP Tour in June.

“There were periods in the match where I played some really good stuff,” he said.

“But there were some where I didn’t – especially in the first set – and that was costly for me.”

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• Day four preview: former champions in action

Murray sticks with Verdasco in hard-fought opening

Murray, now ranked 382nd in the world and unseeded, had the fortune of avoiding a high-ranked opponent in the first round, battling back to beat 448th-ranked James Duckworth – the Australian also on the road to recovery after long-term injury – in three sets on Monday.

That pitted him against two-time US Open quarter-finalist Verdasco, who Murray said he expected to test his movement – and the Spaniard did exactly that.

The pair traded four break points in the opening seven games, Murray missing a set point at 5-4 when Verdasco rescued it with an ace out wide.

That proved pivotal as Verdasco grabbed the momentum to break in the next game and hold out for the early advantage.

“I hit a lot of mistakes when I was up in that set. I feel like I should have won the first set and didn’t,” said Murray.

Murray was undeterred, however, breaking for 3-1 in the second set as Verdasco’s service game began to unravel.

The pair exchanged breaks again as Murray moved 4-2 ahead before the Spaniard produced a double fault on set point to allow the former world number one to level.

Verdasco upped his service game in the third set, landing 71% of his first serves to break twice and ensure the match would go to four sets at least.

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‘I don’t want to say Andy lied’

Both players disappeared off Ashe at the end of the third set after Verdasco took the 10-minute extreme heat break which was again implemented by US Open officials.

When Murray returned to court, he complained Verdasco was talking to his team in the locker room – which is against the rules.

“When I came out of the shower, his coach and one of the Spanish doubles players was in there chatting to him, and you’re not allowed to speak to your coach. I went and told the supervisor,” Murray said.

“I’m not blaming Fernando and his team. They probably weren’t aware that that was the rules. They certainly weren’t trying to break any rules.

“It shouldn’t be for the player that’s competing against him to have to go to the supervisor.”

However, Verdasco denied he was talking to his coach, saying he was only there to go to the toilet.

“I was in the ice bath with Marcos Baghdatis and his coach,” Verdasco said.

“I don’t want to say that Andy lied, but I didn’t talk one word with my coach or any one member of my team.

“I know exactly the rule and I don’t want to be the one breaking it.”

Murray refuses to give up as Verdasco wobbles over the line

After the heat break, a composed Verdasco controlled the fourth set and headed towards victory after breaking for 4-3.

That was until an 11-minute final game when the Spaniard combusted with a third-round match against Argentine third seed Juan Martin del Potro in sight.

His previously reliable serve disappeared as he coughed up five break points, produced two double faults and hit some wild shots in a dramatic final game.

Verdasco also furiously complained after being given a time violation before eventually ending Murray’s resistance with a 104mph second serve – his fastest of the match – which forced Murray long on the third match point.

“At the end when my back was against the wall, I came up with some good tennis to make it close and interesting and almost got myself back into it,” Murray said.

“But there were too many ups and downs for my liking.”

Encouraging, but a long road ahead – analysis

BBC tennis correspondent Russell Fuller

These three hours and 23 minutes reminded us exactly what we have been missing.

Murray offered flair, heart and resilience, mixed in with a familiar dose of confrontation and a long-running one way ‘conversation’ with his coach Jamie Delgado.

Even when seemingly running out of gas in the fourth set, he still managed to create five break back points in a final game which lasted over 12 minutes.

Unsurprisingly, so soon in his comeback, Murray’s unforced error count was higher than he would wish for. But in the early stages especially, he played as close to the baseline as possible, and significantly inside it when Verdasco lined up a second serve.

It has been an encouraging US Open, but Murray knows there is still a long road ahead.

Norrie fails to take his chances

British number two Cameron Norrie’s bid to reach the third round of a Grand Slam for the first time came to an end only moments after Murray’s defeat.

The 23-year-old world number 67, who has enjoyed a rapid rise up the rankings since turning professional in spring 2017, was not helped by his 58 unforced errors against Lajovic.

His match mirrored Murray’s as he fought back from a set down to take the second before failing to take his chances in the next two sets – managing to convert just three of his 14 break points in a match lasting almost three hours.

Norrie was also penalised a first serve for returning late from the 10-minute heat break after the third set. The unhappy Briton told the umpire he had been assured by officials he had enough time.

Defeat for Norrie and Murray means there are no Britons left in the men’s or women’s singles after Kyle Edmund, Johanna Konta and Heather Watson were knocked out in the first round.

Meanwhile, in the men’s doubles British brothers Ken and Neal Skupski were beaten 7-6 (7-4) 7-6 (7-5) by Radu Albot and Malek Jaziri.