Tennis - Mexican Open - Men's Singles - Quarter-Final - Acapulco, Mexico - 02/03/17 - Serbia's Novak Djokovic rests during the match against Australia's Nick Kyrgios. REUTERS/Henry Romero
BELGRADE (Reuters) - Novak Djokovic has lost the tenacity which enabled him to rule men's tennis for a number of years, former mentor Niki Pilic said on Saturday.
"Djokovic reached the Mount Everest of tennis last year after winning the French Open," Pilic, who guided the Serb as a junior at his Munich academy, told Bosnian daily Nezavisne.
