great tennis match

I've been awake for 23 hours straight now, so I'm planning to grab a quick nap after the tennis is over.  But I have a feeling that we're going to be here for a while.  Djokovic and Nadal are both so good that whenever I watch them, I regret that I do not watch more tennis.  However, health may impact play at some point here.  Djokovic just twisted his knees like four times in a row.  Nadal has him running all over.