It started in a playful enough manner when a fan shouted "are you kidding me" at John McEnroe as he was set to hit the opening serve of his "Legends of Tennis" exhibition match against Jim Courier at Copps Coliseum in Hamilton on Saturday night.
That's one of the irascible McEnroe's signature lines and the early part of the match was marked by wise cracks and good-natured banter from a modest crowd of 2,000 or less.
There was an unfortunate early incident when, on one point, a fan twice shouted out as McEnroe was about to hit the ball on his serve. He protested to veteran umpire Dennis Huss of Waterloo, Ont., and wanted a 'let' but was denied. Huss made a request to the crowd to not shout out during serves and there were no further incidents.
In the sixth game of the opening set, with the tennis heating up and people enjoying the fine calibre of play and excitement of watching two former world No. 1s, McEnroe succeeded in sucking all the air out of the building with a single outburst featuring the F-word.
Complaining about a line call that went against him, he began to harangue Huss and it all seemed like him just doing his familiar argue-with-the-umpire schtick until he blurted out, within hearing range of a sizable portion of the crowd, "stop being a 'freaking' clown." He then proceeded to continue bullying Huss, suggesting, in so many words, that he didn't know his (inconsequential) role in an exhibition match and saying he could be replaced.
Huss, to his credit, was not completely cowed, and gave McEnroe a warning.
The use of the F-word was bad enough, but it was as more the context of the crowd settling in for a fun, light-hearted evening only to have McEnroe brutally transform the mood in the arena.
Ultimately, the exhibition featured an inspired display by McEnroe, still in possession of much of the shot-making genius that has made him a one-of-a-kind player in tennis history.
After his obscenity, McEnroe was notably more subdued, almost (though not likely) as if he felt guilty about what he had done. He wound up winning 6-3, 6-4 and made some spectacular volleys, drop shots and half-volley pick-ups against a man 12 years his junior.
At the end, he shook hands with Courier at the net and pointedly avoided shaking hands with the umpire by making a little turn at the net post and stepping out to accept the applause of the crowd.
John McEnroe has been getting away with outrageous behaviour his whole career, on the main tour and as a senior competitor. Several years ago, a contemporary of McEnroe's on the pro tour took his two young sons to a senior event but walked out midway through the first set because of McEnroe's obscene language and rude antics.
McEnroe is now 51 years old and is parenting six children but is still incapable of acting like an adult on the court.
There is a sense of entitlement that has been imbued in him, a coddling by officials of all kinds - at tournaments and in his work in broadcasting where he can be a prima donna - that has resulted in him knowing he can do whatever he likes with impunity.
After Saturday night, McEnroe probably returned home to New York and told friends he had played in Hamilton and beat Courier without ever mentioning the ill-timed obscenity that poisoned a good vibe in Copps Coliseum.
He should have to do what any of his children would likely have to do in the same circumstances - apologize to the spectators, to the organizers, the umpire and any other well-meaning people involved in the event.
But it will not happen - he has gotten away with similar conduct so many times and is all too aware he's bulletproof.
So it he will take the money - a rough estimate of about $75,000 (U.S.) for the match - and run, and one more time thumb his nose at civility and decorum.
Late in the match, a man in the crowd called out, "Johnny, smile," with absolutely no response from the dour individual who is, by turns, the epitome of brilliance and boorishness.
It's pathetic, it's sad. Tennis's spoiled child has never grown up.