World No 1 Novak Djokovic was disqualified in the US Open fourth round on Sunday after hitting a female line judge in the throat with a ball in the first set of his match against Spain's Pablo Carreno Busta. Djokovic was becoming frustrated after failing to take the opening set, suffering a fall and having dropped serve to trail 5-6. The Serb has a history of on-court flare-ups, most usually ending with his racquet being smashed to smithereens. Above is a picture gallery of times the 17-time Grand Slam champion lost his cool. Simply click on the arrows or swipe.