Watch as Alexander Zverev outlasts Novak Djokovic, firing a backhand passing shot winner down the line to win the biggest title of his career at the Nitto ATP Finals. Zverev said: 'This is the biggest title of my career so far. This trophy means a lot, everything, to all the players. I mean, you only have so many chances of winning it. You play against the best players only. How I played today, how I won it, for me it's just amazing.'