Andy Murray lost a fiery encounter with Fabio Fognini in the second round of the Shanghai Masters after twice failing to serve it out.
The performance itself gave more than enough talking points, with Murray raising his level again to push a player ranked 12 in the world all the way before slipping to a 7-6 (4) 2-6 7-6 (2) defeat.
Murray was furious with Fognini, who is no stranger to overstepping the mark, when he shouted as the Scot was about to put away a volley in the 11th game of the deciding set.
Murray confronted his opponent at the change of ends, telling the Italian to "shut up" as umpire Fergus Murphy tried to dissuade him from taking it any further.
The Scot said during the change-over: "When I have a volley on top of the net, he shouts and then tells me 'don't look at me' - he shouted in the middle of the point."
Murray then shouted towards Fognini, saying: "Mate, you do it all the time, to everyone. Shut up!"
Murray said after the match as reported by the Daily Mail: "The sound came from him, which you're not allowed to do, it's against the rules, it's hindrance, you shouldn't do it.
"Fabio wanted to engage with me, I probably shouldn't have done, but I am not having him talk to me like that on court."
Having failed to serve out the match at 5-4, Murray had another chance at 6-5 but Fognini broke back once more and then dominated the tie-break, clinching victory after three hours and nine minutes.
The handshake between the pair was brief, with Murray continuing to press his point to Murphy before leaving the court.
Murray has had many tough tussles with Fognini over the years, winning four and losing three of their previous seven matches.
The Italian landed the first blow with a break of the Murray serve to lead 2-1 only for Murray to reel off three games in a row, securing the second break with a backhand winner flashed brilliantly cross-court.
However, Fognini produced some high-quality points of his own to get back on serve immediately and, after both men had survived pressure on their own serves, it was the Italian who edged the tie-break, a double fault proving costly for Murray.
The Scot responded very well, breaking Fognini for 3-2 in the second set and then making it five games in a row after his opponent had a mental lapse.
He was back fully focused at the start of the decider, though, and it was nip and tuck all the way through to the dramatic final stages.
Cameron Norrie was also beaten in the second round, losing 6-3 6-1 to US Open finalist Daniil Medvedev.
Roger Federer on the other hand marked his return to the tour with a straight-sets victory over Albert Ramos-Vinolas.
Federer, who had a bye in the opening round, had only played in the Laver Cup since his shock loss to Grigor Dimitrov at the US Open and was content with a 6-2 7-6 (5) success against his Spanish opponent.
On Federer's mind was the fact he had lost the last time they met, at the same stage of the same tournament four years ago, but the Swiss fought back from 1-4 in the second-set tie-break to shut down any chance of a repeat.
"He had his chances but it was a nice comeback for me and, overall, I was very happy," said Federer on atptour.com.
Gael Monfils' hopes of qualifying for the ATP Finals next month suffered a blow as he lost 6-2 7-6 (1) to Hubert Hurkacz.
In the first round, Andrey Rublev upset 12th seed Borna Coric and there were also wins for John Isner, Matteo Berrettini, David Goffin and Felix Auger-Aliassime.