Murray has it, loses it

Murray went up two sets, both in tiebreaks, even though by he and del Potro played lots of loose points. Del Potro's left knee looked a bit loose, too, and it seemed he might retire at 3-4 in the third after a lengthy visit with the trainer.

So, naturally, del Potro reeled off the next three games and took the third set, and now looks pretty darn healthy. They've been on the court for 3 hours. I think Rafael Nadal and Mardy Fish will take the court around sun-up in Barcelona.