His win over Djokovic calls into question the Big Four 's dominance .
Wawrinka defeated Novak Djokovic , 4 - 6 , 6 - 4 , 6 - 3 , 6 - 4 , at the 2015 French Open .
Wawrinka 's win Novak Djokovic Djokovic calls into question the Big Four 's dominance .
Wawrinka defeated Novak Djokovic , 4 - 6 , 6 - 4 , 6 - 3 , 6 - 4 , at the 2015 French Open .