Mouratoglou calls Kyrgios' serve the best of all time on ATP Tour with Roddick in top five

Nick Kyrgios has a fabolous serve and for noted tennis coach Patrick Mouratoglou, it's actually the best of all time which is very high praise for the Australian.

Picking between individual serves is pretty tough but a tennis coach should know. According to Mouratoglou, Kyrgios has the best serve of all time which he explained through a few points. According to the Frenchman, the Australian is the best today and that speaks volumes with the sport having the better returners now than before:

"Kyrgios is number one because players return much better today and he's undoubtedly the current best."

Speaking about other players, Mouratoglou mentioned Isner as number two and Roddick as number three:

"Andy had the most violent way to hit a serve in the tennis history."

He placed Karlovic 4th:

"Thanks to his (Ivo Karlovic) height, he made a great career mostly based on his serve."

And Sampras 5th:

"Pete had the most unpredictable and unreadable serve both on first and second."