I don't know, in terms of probability, I'd guess this is more like a 30-35 inning baseball game. Just thinking simply, there have been 59 times someone was up by one game, each of those 59 times the person trailing won the set. (1/2)^59 = 1/576460752303423488 Now, my coin flip assumption might not be fair, but that is absolutely absurd. Historically, what are the odds of an inning where both teams score the same number of runs? This is far longer than any tennis match ever, and it's not even close.