For as bad as Fed's been, the fact that it's still close shows how bad Murray's been a lot of the time. Silly errors and not capitalising on chances.
Yeah, Murray's return and backhand have been excellent, but there have been a lot of basic forehand errors. Total gift of a break in game 2 as well, and poor on these bps in the 2nd set.
He's looked off all week, probably because of the cold, but no question he gets extra motivation playing Federer. Perhaps that combo is why the strange mishmash of a performance.