sner, who holds the record for the fastest recorded serve at an ATP Tour event of 157mph, is 6’10” tall.
He has also hit the most aces (14,470) in ATP history, ahead of Karlovic (13,728), who is 6’11”.
Giovanni Mpetshi Perricard, who set the record for the fastest serve in Wimbledon history last year with a 153mph rocket, is 6’8″.
But height – and speed – is not everything when it comes to serving.
TNT Sports experts Jim Courier, Isner and Sam Querrey discussed who are the greatest servers that are not as tall as Karlovic and company.
Among the names mentioned was current world No. 1 Jannik Sinner, who is 6’3″, and Courier says is ”turning into an amazing server”.
Isner added: ”I think when Sinner started working with [coach] Darren Cahill they changed his service motion a bit. It went from the platform serve to the pin-point serve, where you step up. I think his serve improved after that.”
Courier said Pete Sampras, who measured in at 6’1″, was the first person he thought of and also praised Novak Djokovic for how his serve has become one of the ”greatest of all time”.
On Djokovic, who is 6’2″, Courier said: ”I would be remiss not to mention someone whose serve didn’t start out great and early on you’d be more worried about his return – and that’s Djokovic.
”His serve as his career has gone on has become one of the greatest serves of all time if you look at the cold numbers.
”He has a very high first serve percentage but most importantly his accuracy to the line. He has become like Roger Federer and like Sampras, very close to the line, and that accuracy matters.”
Querrey said he was impressed with how Roger Federer, who is 6’1″, came up with big serves at the most crucial times in matches.