Video: This is why Roger Federer is a legend!

Roger Federer stopped serving against his countrymen Stanislas Wawrinka during Basel 2011 semi-final when he saw a mistake with score on the screen. The actual score was supposed to be 30-30 but  the board showed 40-15 (in favor of Federer) and on match point. But, Federer convinced the chair umpire to change the score to 30-30. Kudos!