Alexander Zverev landed the biggest win of his career by shocking Novak Djokovic to win the ATP Finals on Sunday. The 21-year-old German, who was booed by indignant Roger Federer fans after beating their idol 24 hours earlier, saw off the world No 1 6-4 6-3. Zverev delighted the crowd during the post-match ceremony with quips and jokes that kept them laughing.