Is he the only one who can do that serve consistently on tour today? You know the one that lands midway down the line and curves to the right, kind of like a lefty serve. It is not powerful but manages to throw his opponent way off every time. Also, because of the fact that so few pros can do that, it is a very effective surprice tactic. And the way he deliberately hits it short is pure genious, landing short gives the ball more time to curve away from his opponent making it more dangerous. Also, I don't know how he does it but that serve bounces surprisingly low, I think it is an extreme slice serve if there is such a thing. That serve is probably the most difficult serve to pull out but it is so effective when done right especially against righthanded opponents (hence done right.) It is like facing a server with a right and lefthanded 2nd serve and you never know which one you'd get until it is too late.