The SABR (Sneaky Attack by Roger) was one of the most interesting Federer's shots in 2015, with the Swiss returning some serves really inside the court. In a recent interview, Stefan Edberg, who was Federer's coach at the time, said: 'In his sneak attack, Roger brought something interesting and new to the game. I don’t think many players can do it. Whether SABR should be permissible or not, I somehow found it very interesting. At the same time, it was shocking, but he won most of the points from it. If you do it 10 times and win six-seven points, the percentages are on your side.'