An extraordinary mid-match pep talk from the chair umpire has fired Nick Kyrgios into a US Open third-round blockbuster with Roger Federer in New York.
Swedish official Mohamed Lahyani is already under fire for his unprecedented intervention but Kyrgios rolls on after pulling off a drama-charged 4-6 7-5 6-3 6-0 comeback win over Frenchman Pierre-Hugues Herbert.
Kyrgios was trailing 3-0 in the second set, having thrown away the first on a wild second-serve double-fault, when Lahyani left his chair to beg the Australian to start trying for the sake of the paying crowd and to avoid being sanctioned — again — for not giving his best effort.
"I want to help you. I want to help you," Lahyani said.
"I've seen your matches: you're great for tennis.
"Nick, I know this is not you."
The US Open released a statement from tournament referee Brian Earley, in which it was suggested Lahyani only stepped down from his chair due to the level of noise in the stadium and that the experienced umpire was checking whether Kyrgios was suffering an injury or not.
Kyrgios said, "Okay, just call the trainer to the court and I'll try."
But when the trainer arrived and asked what Kyrgios needed treatment for, the Australian said, "I don't know, check my wrist or something … can you just stay out here for like two minutes?"
The umpire's controversial "coaching" was savaged on social media, with fans furious about his perceived bias towards Kyrgios and claiming it was unfair on Herbert.
Kyrgios 'not to blame'
The USTA, already under siege over a succession of rules blunders this grand slam, was also understood to be unimpressed with Lahyani's conduct and investigating the incident.
But it certainly seemed to work for Kyrgios, who hauled himself back into the contest having looked utterly disinterested in the early stages.
Yawning one second, Kyrgios delivered a return winner the next to break Herbert to get back on serve at 4-5 in the second set before offering a subdued fist pump towards his box.
He clinched the tiebreaker to draw level and then break Herbert early in the third set to take command.
Totally revitalised, Kyrgios dropped just three games in the final two sets, sealing victory after two hours and 47 minutes.
Herbert wrote in a statement — in both French and English — that he did not blame Kyrgios for the intervention, but said questions needed to be asked of umpire Lahyani.
"I did not hear the discussion between Lahyani and Nick and it did not affect me at all," the Frenchman wrote.
"Nick from his side is not to blame as he did not ask for anything. But his behaviour and motivation on court changed from this moment and then he dominated the match.
"On the other hand, after seeing the video, I am angry against the umpire.
"He should not go down of [sic] his chair and try to reason [with] Nick. Did this action affect the game? We will never know."
Herbert also hit out at the United States Tennis Association [USTA] after they released a statement siding with Lahyani, suggesting the umpire should not be sanctioned.
"I am even more upset against the statement of the USTA that is clearly taking us for fools," Herbert said.
"[To] err is human but I still wait for explanations.
"When we players are making mistakes on court we are sanctioned."
Kyrgios was also active on social media, hitting back on twitter at Croatian women's player Donna Vekic after the world number 41 weighed in on the matter, referencing that women players are able to receive on-court coaching on the WTA Tour.
'It won't happen again': Federer
Federer later advanced to the third round with a straight-sets win over Frenchman Benoit Paire, 7-5, 6-4, 6-4, confirming a Saturday showstopper with Kyrgios — almost certainly under lights at Arthur Ashe Stadium, world tennis's biggest stage.
The five-time US Open champion said he did not think it was a good look, when asked about the incident after winning his match.
"It's not the umpire's role to go down from the chair, but I get what he was trying to do," the second-seeded Swiss said.
"He [Kyrgios] behaves the way he behaves. You as an umpire take a decision on the chair, do you like it or don't you like it. But you don't go and speak like that, in my opinion.
"I don't know what he said. I don't care what he said. It was not just about, 'How are you feeling?' 'Oh, I'm not feeling so well'. Go back up to the chair. He was there for too long.
"It's a conversation. Conversations can change your mindset. It can be a physio, a doctor, an umpire for that matter. That's why it won't happen again. I think everybody knows that."
Asked after the match what the umpire was saying to him when he trailed by a set and a break, Kyrgios said: "He was just concerned about how I was playing, like, 'Nick are you okay?'
"I know what I was doing out there wasn't good. I wasn't really listening to him [Lahyani]. Didn't help me at all.
"He [Herbert] let me back into that set. He should have just served it out.
"I stayed out here in the second set. I had no real choice."
Millman, de Minaur also progress
Elsewhere at the US Open, Australian John Millman scored one of the biggest wins of his career to charge into the third round.
Millman, the world number 55, upset 14th-seeded Italian Fabio Fognini 6-1, 4-6, 6-4, 6-1 to progress to the last 32 for the second straight year at Flushing Meadows.
A winner over Kyrgios last year, Millman was thrilled to embark on another great run in the Big Apple.
The Queenslander's victory set up a clash with unseeded Kazakh Mikhail Kukushkin, himself a surprise straight-sets winner over Korean young gun Hyeon Chung.
Victory over the world number 84 would catapult Millman into a last-16 showdown with either Kyrgios or 20-time grand slam champion Roger Federer.
Alex de Minaur also made a fuss-free entry to the third round.
The teenage ace could hardly have been more impressive in taking out highly rated young American Frances Tiafoe 6-4, 6-0, 5-7, 6-2 to reach the last 32 for the second successive grand slam.
"I had to play my best tennis today," de Minaur said.
"All credit to Frances, I just had to be very tough throughout the whole match and try to keep my concentration and not get down on myself and always stay positive.
De Minaur next plays Croatian seventh seed Marin Cilic, the 2014 champion, who easily dispatched Polish qualifier Hubert Hurkacz in straight sets, 6-2, 6-0, 6-0.
Matt Ebden and Ajla Tomljanovic both lost.
In a high-quality thriller, Tomljanovic missed a match point deep in the third set of a 6-2, 6-7 (3/7), 7-6 (7/4) defeat at the hands of Czech doubles specialist Katerina Siniankova, while Ebden ran of steam against Philipp Kohlschreiber, going out 6-7 (1-7), 6-3, 6-2, 6-0 to the German.
Wozniacki humbled as other women's seeds progress
Second seed Caroline Wozniacki fell to a straight sets defeat to world number 36, Ukranian Lesia Tsurenko.
This year's Australian Open champion was humbled 6-4, 6-2 on the Louis Armstrong stadium show court in the evening session.
Elsewhere in the women's draw, the majority of the seeds continued their progression with minimal fuss, although fourth seed Angelique Kerber did need three sets to see off Swede Johanna Larsson 6-2, 5-7, 6-4.
Fifth seed Petra Kvitova dispatched Chinese world number 79 Yafan Wang in straight sets, 7-5, 6-3 and last years finalist Madison Keys breezed past fellow countrywoman Bernarda Pera in just 72 minutes, 6-4, 6-1.
However there was disappointment for 11th-seed Daria Kasatkina and Canadian favourite Eugenie Bouchard, who both bowed out in straight sets to Aliaksandra Sasnovich and Marketa Vondrousova respectively.