For some odd reason a classic clay encounter between del Potro and Nadal on Davis Cup is frequently forgotten. JMdP gave a helluva of a fight that day, won the first set 6x1, and was a up a break and 40-0 while serving in the second... (strangely enough, DS was also 40-0 and a break up in the second in their match. You cannot give nothing to Nadal...).
This one has "classic" written all over it, even if both are not playing their absolute best. But both are playing quite good, it is a big stage, both really want it. Barring injury -- which for some reason I keep thinking will happen quite soon in the match to one of them -- it could be a hard fought and entertaining match, specially if del Potro manages not to go down 0-2.
One odd thing about this matchup is that the both forehand-backhand cross court rallies are completely favorable to the forehand side. The DTL forehand will probably appear just as a point finisher, because it would be in general a quite silly rally shot.
The two keys for me for the match are Nadal's number of UFE's and del Potro's serve. If Nadal is connecting, only a field day on serve can save del Potro, while if del Potro is serving well, Nadal cannot afford to miss much.
(just realized I haven't posted this earlier when I finished writing it, now the match is under way, better late than never).