Well, it seems that you are quite interested in that guy huh? So, he is a very great tennis player. Anyway, the type of glasses he wears on a regular basis is quite special as you can see, we often call it semi-rimless glasses. However, you should know that his glasses must be specially designed for sports utilities, which is quite complicated , maybe them could resist some reflective lights or something. You could find those glasses at some professional sports shops.
It is said that janko tipsarevic wears the oakley eyeglasses. If you want to wear the similar type, you could go to the near real store of eyeglasses to see whether there is such popular type. Or you could go to the online store to have a check. Usually the price in the online store will be cheaper than those in the real stores.