On the eve of the ATP World Tour Finals the 17-times grand slam champion Roger Federer says he wants more blood testing done in tennis to help keep the sport clear of doping.
Britain's newly-crowned US Open champion Andy Murray raised the subject this week at the Paris Masters, suggesting there needed to be more out-of-competition checks.
World Tour Finals title holder Federer says his Scottish rival has a point.
Federer says he feels he's being tested less now than he was six or seven years ago and says it's vital the sport stays clean.
According to figures on its website the International Tennis Federation, the sport's governing body, carried out only 21 out-of-competition blood tests in the professional game in 2011.
Cycling's governing body the UCI carried out more than 3,314 out-of-competition blood tests in the same year.