“It was not easy, because everybody wanted to know who am I,” Karlovic said during an interview this month in Paris. “It seemed for me that the interview lasted all day. It was hard for me to speak in front of a lot of people, and back then it was even worse. But you know, I am glad that I did it, because you just have to do it if you want to become a good player.”

Eight years later, Karlovic has indeed become a more complete player and a well-established threat, although after peaking at No. 14 in the rankings in 2008, he is back in the role of outsider at age 32. Having missed the second half of last season with an Achilles’ tendon injury that required surgery, he has since slipped to No. 143 in the rankings and had to rely on his protected ranking to get into the main draw at Wimbledon.

Yet he remains one of the players that the leading men would least like to look up (and up) and see across the net on grass. With his exceptional reach and leverage, Karlovic can generate acute angles and brute power with his serve like no other player in the history of the game. He hit the fastest serve ever recorded in Davis Cup last year: 251 kilometers per hour, or 156 miles per hour.

Although endurance and mobility remain an issue at his size (he weighs 110 kilograms, or 245 pounds), he has added variety to his baseline game and improved his touch around the net.

But as his profile has dipped on court in the last year, his profile in cyberspace has risen since he opened a Twitter account in July. Even though Karlovic’s ability to speak fluidly in public has improved, his stammer endures. With Twitter, though, he has found his quick-hitting medium, and his messages — usually in English, his second language — are often pithy and often earthy (and sometimes both).