It was a hard fought hard court match between two big servers. del Potro actually was struggling with his serve for most of the day; it wasn't until late in the 3rd set that his serve started creeping over 120 mph. Isner was serving well over 120 mph and even served up to 139 mph and a few 125 mph out wide into the corner of the service box.
del Potro is now undefeated against Isner in 4 matches, and today's title was his 15th career title. Isner is still at #1 on the standings of the US Open Series with 115 points and del Potro is now #2 with 70 points.