And Del Potro breaks back again to send the Argentine ultras into raptures!
A wonderful shot from Del Potro. 
This is turning into one of the matches of the year.
Del Potro has found another gear here. Vital game now though.
Juan Martin Del Potro is playing superbly.
There are also some extremely pretty ladies in the crowd.
To quote Kenny Powers. Martin Del Potro has an arm like a fucking cannon.
Incredible scenes here! Del Potro to serve for the fourth.
It’s unbelievable. Any time he remotely gets into a point at the moment he just pulversises a couple of balls and wins it. Haven’t seen him play like this since he won the US Open. Fantastic stuff, even if he ends up losing here it’s a good sign that he should be back to his best next season.
And this is on clay as well Braz. An awesome display of Tennis from Del Potro.
Great point from Nadal there to break back. Del Potro bottled it a bit though when serving for the set. That double fault at 30-30 was very feeble.
Such a time for Del Potro to double fault.
I hate when they warn the crowd like that in Davis Cup games. They should be encouraging atmospheres like this in tennis.
+1
Del Potro’s game has fallen apart a little since he served for the set. The end is nigh.
Rafa serves for the Davis Cup.
Thought JMDP had the break there. Some point. One more break point though.
This is one of the best sets of tennis I’ve ever seen. Hope Del Potro takes the tie break to give us a fifth.
Del Potro breaks back.
Tie break!
Rafa’s record in tie breaks is sensational. 5-0 up here in the tie break.