Answer
Three players have achieved major wins against each member of the Big Four (Roger Federer, Rafael Nadal, Novak Djokovic, and Andy Murray): Novak Djokovic, Rafael Nadal, and Jo-Wilfried Tsonga. Tsonga's victories over these top players include defeating Federer in the 2011 Wimbledon quarterfinals, Nadal in the 2011 Canadian Masters final, Djokovic in the 2012 Shanghai Masters semifinals, and Murray in the 2013 French Open quarterfinals.