The fastest tennis serve ever clocked at 263 km/h
Australia's Sam Groth hit a serve so fast the ball crossed the net before opponents could plant their feet.
On 9 May 2012, Australian Sam Groth served an ace measured at 263 km/h (163.4 mph) during an ATP Challenger event in Busan, South Korea - the fastest serve ever recorded, as recognised by Guinness World Records.
Because it came at a second-tier Challenger rather than the main tour, the speed sits slightly outside official ATP tour statistics. The fastest serve at a top-level ATP event belongs to John Isner, at 253 km/h (157 mph) in the 2016 Davis Cup.
At 263 km/h, the ball needs only a fraction of a second to travel the length of the court.
Serve speeds like these explain why returning a big server can feel less like a rally and more like reflex - the swing is mostly over before the brain registers the ball.
Sources & references
2 referencesWell-established. Corroborated by 2 independent sources.
