BERLIN (Reuters) - Croatia's Ivo Karlovic unofficially broke the fastest serve world record when he fired a 251 kph effort during his country's Davis Cup tie against Germany in Zagreb.
The 2.08m-tall Karlovic, back from Achilles surgery, was partnered by Ivan Dodig and produced the serve in the fourth set of their losing doubles rubber on Saturday against Philipp Petzschner and Christopher Kas.
If recognised he will beat current record holder American Andy Roddick, who has a best mark of 249.4.
"He hit a 251 kph serve in the fourth set, which if recognised would be a new world record," Davis Cup organisers said on their website (www.daviscup.com).
(Writing by Karolos Grohmann; Editing by Patrick Johnston)