I had the same feeling

I thought Nadal is going to come back and I was worried (I was betting Novak to win), because all the momentum was on Nadal's side. But Novak took a  medical timeouts, took some pills while Nadal was waiting unpatiently.

Then after the timeout, Nadal was not the same Nadal in the third set, he was barely moving, then I saw him touched his legs a little bit, then I thought he might got insured or cramped on his legs, and that is why in the 4th set, a lot of balls, he did not even bother to touch it. Truely strange for Nadal in the 4th set.

Anyway, I am happy because I won my bet, hehe...

Just my observation ...