Ivo Karlovic broke the world record for the fastest serve in a Ivo Karlovic match in March . The Croat was clocked at 251 kph ( 251 kph ) to beat Andy Roddick 's previous mark . In 2002 , the International Tennis Federation ( ITF ) included a new , larger tennis ball in its official rules . Type half tennis balls were introduced by the ITF in March , and are 6 % bigger in diameter . They are seen as a potential solution if the number of aces begins to increase .
Ivo Karlovic broke the world record for the fastest serve in a Ivo Karlovic match in March . The Croat was clocked at 251 kph ( 251 kph ) to beat Andy Roddick 's previous mark . Type half tennis balls were introduced by the ITF in March , and are 6 % bigger in diameter . They are seen as a potential solution if the number of aces begins to increase .