Andy Murray did not just beat Roger Federer for the first time in grand slam play at the Australian Open on Friday, the Scot's relentless onslaught made the King of Cool lose his cool.
The regal Federer, whose grace and skill has dazzled the sport for a golden decade in which he has won 17 grand slam titles, rarely appears ruffled by anything but on Friday, in the heat of battle, his mask slipped.
Struggling to live with Murray's power and unable to punch through the Briton's granite-like defences, the 31-year-old Federer fought like a cornered rat to force a riveting contest into a fifth set.
Throughout the four-hour semi-final Murray showed scant regard for his opponent's reputation, engaging the Swiss maestro in the kind of close-quarters combat that left little room for the decorum and reverence often accompanying Federer matches.
Early on as Murray dominated BBC commentator Andrew Castle was forced to apologise on behalf of the Swiss for an F-word tirade and when Murray served for the match at 6-5 in the fourth Federer uttered some choice words in his direction.
Murray's nonchalant smirk across the net was followed not long after by a drilled forehand aimed directly at the body of Federer - a tactic once the preferred choice of Murray's poker-faced coach Ivan Lendl.
There was a palpable tension between the two players who one imagines, unlike Murray and Novak Djokovic or Federer and Rafa Nadal, are unlikely to be future drinking buddies.
"Stuff like that happens daily in tennis matches," Murray said when quizzed by British reporters.
"The stuff that people say on football pitches and in basketball and all sorts of sports, I mean, it was very, very mild in comparison to what happens in other sports.
"It's just one of those things."
While playing down the incident, the fact that Murray clearly got under Federer's skin during the match, then withstood a ferocious response from him to come out on top, will be stored away in the Scot's memory bank.
Federer gave everything he could on the Rod Laver Arena, both mentally and physically, but still came up short against a player transformed from the one whose mental strength when it really mattered was often questioned.
Murray's 6-4 6-7 6-3 6-7 6-2 victory took his career record against Federer to 11-9 but despite those regular triumphs, Friday's one seemed to be the most significant.
In last year's Wimbledon final, Murray also dominated before bowing to the old master in a tearful defeat and while he did gain revenge by winning their Olympic gold medal duel a few weeks later, real bragging rights are earned at grand slams.
"To lose them was tough," Murray said of Friday's two tiebreaks. "I was just happy with the way I responded after both those sets.
"I've lost some tough matches against him in slams. I'm sure both of us will play each other again in slams, so it will help having won once against him."
With Lendl in his corner, Murray is now the real deal. Gone are the sloppy service games, the passive returns and cagey counter-attack tennis that were once his trademark.
Murray has released the beast, fights fire with fire and is ferociously protective of his territory.
While he was a few years behind Djokovic in his "big-match" development, last year's U.S. Open triumph over the world number one Serb was proof that he has caught up and on Sunday they will walk out on court as equals.
(Reporting by Martyn Herman in London; Editing by Alison Wildey)