After his defence of the Wimbledon men's singles title had ended in the quarter-finals in 2017, where he was defeated by Sam Querrey of the United States, Andy Murray corrected an American journalist at the post-match press conference.
"Andy," the journalist began. "Sam is the first US player to reach a major semi-final since 2009. How would you describe the..."
"I beg your pardon?"
"Yes. First male player. That's for sure! How would you describe the adjustments he made today and his overall game?"
On social media, Murray was praised for refusing to allow "casual sexism", and his mother, Judy, tweeted: "That's my boy."
Murray was in an understandably sombre mood. His hip injury, already a feature of his sporting life, was doubtless bothering him as he spoke. There was no answering smile as the journalist laughed, a little self-consciously, over his slip – just a stare.
This incident may have had nothing to do with the fact that Serena Williams agreed to play with Murray in the mixed doubles at this year's Wimbledon.
But, then again, it may have had something to do with it, given that it was a terse but telling indication of respect for fellow athletes, and perhaps one in particular.
At that point, Williams had won 22 of her 23 Grand Slam singles titles so far. And she had reached the semi-finals on each occasion.
There is not going to be any strawberries-and-cream ending at Wimbledon this weekend – Murray and Williams went out in three sets in yesterday's round-of-16 to the number one seeds Bruno Soares and Nicole Melichar.
But their collaborations on – inevitably – the Centre Court in the course of this week will be remembered as one of the features of this year's Championships.
After their second round win over Fabrice Martin of France and Raquel Atawo of the United States, Bonnie Greer, the American-British playwright, novelist, critic and broadcaster, who has lived in the UK since 1986, tweeted: "Don't like watching #sport, but it was on when I came in...and I saw end of #MurRena/#SerAndy-mixed doubles. #Serena commanded what I saw...and Andy aced it to shut it down. A fab example of a woman and man working together and friendship."
I did the same as her, and it was fascinating to see two players so used to relying on themselves sharing a space and a game.
Murray and Williams were not included in the 16 seeds who were exempt from playing the first round, and rightly so. They had never played together before, and on occasions that was shown up clearly as they were drawn out of position or went for the same ball.
But that was part of the appeal of watching them – seeing two champions adapting to new challenges and compromises.
Another particular element about watching this particular pairing was the different directions from which they were arriving to play.
For Murray, whose sporting life has been wretched with pain and doubt for the best – or rather the worst – part of two years as he has struggled with a hip problem that he clearly felt, earlier this year, was about to end his career, an outing into the world of tennis doubles – men's and mixed – has offered him a way to stay inside the game he loves as he recovers from the serious operation he had earlier this year to "resurface" the damaged areas.
The angst and torment of singles is absent. For him, and for those watching him, this has been pastoral.
"Only playing in the doubles at Wimbledon is obviously different to playing in the singles and it has been a new experience for me," he told BBC Sport this week. "The tournament has been more relaxed.
"I've enjoyed Wimbledon every time I've had the opportunity to play – it is just a little bit more stressful when you're playing singles. When it is doubles you are sharing that load together, which helps."
As for Williams, she is still involved in the sharp end of things, and is now only two matches away from a 24th Grand Slam singles title.
So that she should take the time off from that quest, particularly having had to recover from physical setbacks that were potentially fatal in the course of the last couple of years, is all the more touching. She didn't have to do it – but she clearly enjoyed the experience. It was, in a way, a mark of respect back to Murray.
There were also some memorable incidents which will certainly be replayed again on our screens over the years. Most notably at the point when Murray and Williams had the opportunity of breaking the towering serve of the towering Martin to take the opening set 6-4.
The 6ft 6in Frenchman hammered in a service to Williams from the right-hand court that was timed at 138mph. Williams returned it with interest on the backhand for a winner.
It was an extraordinary moment, with the normal balance of power that exists in any mixed contest being tipped the other way.
A similar result from Murray in the next point would have delivered the set – but he batted Martin's serve weakly into the net, before looking momentarily as if he wanted to disappear into the earth's magma chamber.
Williams was straight over to have a word – and by the way Murray picked up it was probably not "loser".
Wash me in steeped down gulfs of liquid fire, but I couldn't help thinking at that point of the Ray Davies line from Lola – "girls will be boys and boys will be girls".
Too often in recent years mixed sport has been introduced as a quick-fit means of altering the gender balance, nodding to the demands of organisations such as the International Olympic Committee.
But at such moments, the elements in mixed sport fuse into something unique.