Venus Williams violated the Wimbledon dress code on the opening day of the championships when her bright pink bra straps became exposed.
The tournament's rules specify that any visible underwear must be "completely white except for a single trim of colour no wider than one centimetre".
And while 37-year-old Williams may not face any punishment following her victory against Belgian Elise Mertens, she is certain to have been reminded that players are bound to abide by the all-white tradition.
It seemed likely she was served that reminder during a rain break that interrupted the match on Court One, given Williams returned in a different outfit, this time one that satisfied the dress standards.
Tournament officials declined to comment on what, if anything, had been said to Williams about the bra, indicating it would be a private matter if there had been a discussion.
But it was pointed out that the bra was initially hidden from view beneath Williams' dress, becoming exposed only by her movement on court, and that it had not been considered a deliberate attempt to add colour to her outfit.
Williams later reacted to questioning about her clothing by saying: "What pink bra? I don't like talking about bras in press conferences. It's weird.
"I don't want to talk about undergarments. It's kind of awkward for me. I'll leave that to you. You can talk about it with your friends. I'm going to pass."
Five-time Wimbledon champion Williams won through in straight sets, beating Mertens 7-6 (9/7) 6-4 in an hour and 40 minutes.