How should a white belt react if by some miracle he taps a purple belt?

first things first i didn't tap a purple belt.

I'm a white belt, but I've been training at least 3 times a week for 9 months now, so im leaving the realms of total spazzery.

Today we were doing king of the hill, the purple belt was king, i walk up and he's pretty tired, he's on like his 12th roll in a row. he's been crushing for like 20 mins straight.

he sees my white belt with no stripes and pretty much lets me pull guard with 0 resistance (i think he just wanted to rest for a min in the warm safeguard of a white belt).

i caught him off guard with some rubber guard tomfoolery, end up locking in the triangle, can't seem to finish him so i try the Kimora, also no luck, after 45 seconds or so he managed to muscle out and end me.

if i had have come out on top, with everyone watching, what's the most polite thing to do in that situation?

obviously, you don't celebrate, but also i don't want to stone face it and act like its no big deal, but also id want to apologise, but also say thank you.

whats the polite thing to do?