Casper Ruud got his first win against Nadal in the South American Tour in Quito, Ecuador and it was largely thanks to his serve.
As a result of the high altitude, Ruud played an aggressive match, hitting the ball incredibly hard and sending it flying all over the place. A particularly spectacular moment occurred when he delivered the fastest serve of his professional career, a 240 km/h laser that Nadal just watched land in the court.
Such powerful serves are quite rare and generally happen when the conditions are beneficial. The fastest serve ever record was hit by Sam Groth in 2012 and it was 263 km/h. One player came pretty close this year and it happened on clay no less, with no altitude.
At the 2022 Italian Open, Alejandro Davidovich Fokina set the record for the fastest serve of the year and ranked fourth all-time with a 252 km/h delivery. The fact that Ruud's serve is the 19th fastest in history demonstrates how uncommon they are in general.
To be fair, most players are not trying to hit the ball that hard but if they did, we'd have some pretty interesting moments on the tour.