Ivo Karlovic tells The Tennis Space that he doesn’t necessarily buy that Australia’s Sam Groth broke the world’s fastest serve record at a Challenger in Korea last month. Groth allegedly hit a 163 M.P.H. serve, eclipsing Karlovic's 156 M.P.H. serve.

"I was a little bit disappointed, because it was always my goal to have it," the Croat said. "I did it last year and now already it is gone, and Groth’s serve wasn’t on the ATP tour. I don’t have any idea what the speed-guns would have been like at the tournament where he did this. I know that he can hit the ball hard. I don’t usually look at the speed gun on court as when you hit an ace, that’s enough. It’s going to be difficult to beat his record. It’s strange that there was such a big gap between my fastest serve and this new record. Of course, I would like to beat the record."