Picture this.
You're standing on the baseline, sweat dripping, racket spinning. You're down a set and you're down in this set. You need this game to survive. You need to break your opponent's serve.
Now, imagine the ball motoring passed your racquet at more than 260 kilometres per hour. You'd have a better chance of capturing lightning in a bottle than returning that furry-green number back over the net.
I guess that's why you're not being paid the big bucks, though.
From all corners of the globe, here are the players responsible for the top ten fastest professional tennis serves of all time.
1. Sam Groth – Australia – 263.0 kph/163.4 mph – 2012 Busan Open Challenger Tennis
2. Albano Olivetti – France – 257.5 kph/160.0 mph – 2012 Internazionali Trofeo Lame Perrel-Faip
3. John Isner – United States – 253.0 kph/157.2 mph – 2016 Davis Cup
= 4. Ivo Karlović – Croatia – 251.0 kph/156.0 mph – 2011 Davis Cup
= 4. Jerzy Janowicz – Poland – 251.0 kph/156.0 mph – 2012 Pekao Szczecin Open
6. Milos Raonic – Canada – 249.9 kph/155.3 mph – 2012 SAP Open
7. Andy Roddick – United States – 249.9 kph/155.3 mph – 2004 Davis Cup
8. Chris Guccione – Australia – 248.0 kph/154.1 mph – 2006 Davis Cup
= 9. Joachim Johansson – Sweden – 244.6 kph/152.0 mph – 2004 Davis Cup
= 9. Feliciano López – Spain – 244.5 kph/152.0 mph – 2014 Aegon Championships