If you asked me on Tuesday morning, I’m not sure I could have told you who either of these guys were. 100+ 5th set games and a couple of trending twitter topics later, I know who they are.
My biggest question, is how rare is it that neither of these guys can break each other over 100+ games?
From what I could gather from my limited knowledge of Tennis stats each player won around 80% of the points on their serve. I set up a quick sim, based on winning 4 out of 6 points with the server holding an 80% chance of winning each point. That yields the following odds:
Server: 90.3%
Deuce: 8.0%
Returner: 1.7%
Break up the deuce games with the same 80% chance that the server wins by 2 and you get around 97.8% chance that the server holds. That’s incredible.
As it turns out, winning 80% of the points on your serve is a very good thing. The odds of holding serve 59 consecutive games are actually quite high, 27.2%. The odds of two people doing that while winning 80% of points on their serve is 7.4%.
That sounds quite high, but makes sense given that the two players were serving so dominantly. The more incredible thing is that two players serve that well against each other(I can’t imagine their are many matches where each player wins 80% of the points on their serve), in the final set of one of the three majors that don’t use fifth set Tie-breakers. The odds on that are obviously a lot higher.
REXFORD BUZZSAW 
I just did 1,000 sims assuming they hold serve at the 97% rate. Average of 33.87 games. Min 2, Max 214. It will be interesting to see if they keep winning service points at 80% rate, when they are a little more rested tomorrow.