Australia's Sam Groth has fired down the fastest recorded serve in professional tennis, a 263kph rocket that Roger Federer described as "an incredible number".
Groth, ranked 340 in the world, produced the serve in a second-round match against Belarusian Uladzimir Ignatik in a Challenger event in South Korea.
His effort beat the previous fastest-recorded serve of 251kph sent down by Croatian Ivo Karlovic in a Davis Cup tie against Germany in Zagreb in March, 2011.
Federer, speaking at a news conference after clinching a place in the Madrid Open final on Saturday, said he expected the record to be broken again.
"It's not endless but it's definitely only going to go up as the years go by," the world number three said.
"I have actually played with Sam in the past so I know he has a very big serve.
"I didn't know he was 263 kilometres an hour strong but it's definitely big stuff.
"I'm serving maximum at an average of 210 so it's a big deal and it helps to be big and strong and accurate I guess.
"I am sure that eventually there'll be a guy who will break that record too."
While the ATP does not officially recognise serving speed records because of the variance in radar guns it confirmed "the event was using approved equipment, and that other data gathered appeared within a normal range."
Melbourne-based Groth, 24, lost the match 6-4, 6-3.
ReutersTags: sport, tennis, australia First posted May 13, 2012 20:03:09