Tennis is a puzzling sport - you can be up 5:0 and yet lose most of the following games as well as the match itself. Anyone that plays tennis knows about this "

Tennis is a puzzling sport - you can be up 5:0 and yet lose most of the following games as well as the match itself. Anyone that plays tennis knows about this "roller-coaster" (especially visible in WTA). "Unusual" is quite usual in tennis, honestly. You should take it into an account when you do stats. Obviously, people try to exploit this fact to make believable pre-determined matches, but it's really difficult to tell who is doing it, and who is simply more "unstable".