Sorry Feli lost yesterday

I didn't get to see much of the Match at all. But I sure noticed that knee with all that white tape or whatever it was around it

He didn't look at all comfortable on the court. I don't know if the knee was bothering him or something else?
He also didn't serve like he had against Rafa--may be that was caused also by the knee problem? Fish played as well against Feli as Feli had played against Rafa!