Tennis great Rafael Nadal’s Olympics singles career is over after Novak Djokovic beat his arch-rival 6-1, 6-4 in the Paris second round. The Spaniard is still in the doubles along with compatriot and heir Carlos Alcaraz but whether he will be seen on a singles court again remains to be seen. The injury-prone 38-year-old has said this season is probably his last and having gone out of the French Open in May in the first round, skipping Wimbledon and then bowing out early here, a tilt at September’s US Open may now be in doubt. Djokovic leads the way with a men’s record 24 grand slam titles, wit…