Very nicely done from Diego - certainly made people sit up and take notice.
if he'd handled the pressure points a little better that could have been an even tougher match. As it is, the Argentine's chutzpah and Federer's own below-par performance made it hard work.
Gotta love these young players who come out and just play freely with little pressure - no history with the opponent so nothing to dwell on, just swing and play good tennis. Until those pressure moments.
Still, certainly a good match for Hartfield who will have learned a lot about how to handle the pressure of the big points. Nice workout for Federer. I don't think he'll be entirely happy with his performance, but he did enough to get it done in 3 so he won't be too concerned at this point with the parts of his game that didn't click right into place.