I found this article been having trouble translating it but..I thought it was interesting enough to post on the ITF & the doping tests in 2009.

Tennis | Doping
Almost one third of surprise checks of the ITF is not passed
The International Tennis Federation (ITF), responsible for the controls and the fight against doping in professional tennis, has released its report on the inspections of 2009. The 2126 ITF tests performed: 1,972 in competition and 154 out of tournaments, or surprise. The racing controls are almost entirely consummated, but of 154 Out-of-competition, 47 (30.1%) could not be done, not the tennis player to appear within the required period of 60 minutes.
The rules tolerate up to two failures in 18 months. The third appearance in this period generates a two-year suspension. Two appearance in 2009 with a doubles player Mike Bryan and Frenchman Gilles Simon. One's that failed are; Moya, Nadal, Ferrer, Feliciano, Federer, Roddick, the Williams and Sharapova. Nadal was the only monitored twice in the Davis Cup final 2009. And spent more surprise checks. Wimbledon was the tournament that did more tests of blood and EPO.

So.. Is Rafael is drug tested more because he wins more?