Couldn't get my Google page working, but it does now.
I could of sworn Mark Philippoussis served a 142mph rocket but the image below doesn't agree with me.
Here's something interesting I found
here [Speed of the Fastest Served Tennis Ball];
"'Big Bill' Tilden, in 1931, was credited with 163.3 mph [262.8 km/h]. Lester Stoefen, American also, was credited with 131 mph 211 km/h in the 1930s. In the post-war game Jack Kramer was accorded 110 mph 177 km/h and Richard Gonzales 112 mph 180 km/h."
My question is - How/on what instrument was the serve recorded?