Some rules would be good. Maybe describe the run as a three-set tournament. It might be good to have a five and seven as well. And of course to describe the start and end events, just for verbosity.
Here's what I would say:
Run begins when selecting 3 Set and ends at the beginning of the sweep animation that shows the final score of the final round (e.g. 2-0). And of course, the usual caveats, no turbo buttons/messing with emulation speed, no state saves, etc.
It appears that the dice the players are "holding" disappear on the beginning of the sweep. That's a pretty solid indicator.
That's pretty much how I used to time it, but I now added rules:
Time starts on selecting the number of sets and ends on winning the final match.
Frameprecise timing: Timing start: The last frame that the text "HOW MANY PLAY" is visible on. Timing end: The player's dice disappearing.
I don't think milliseconds are necessary yet.