Nick Kyrgios trolls Novak Djokovic on Twitter: How many years would I be banned for?

Nick Kyrgios opened a cheeky Twitter poll Monday asking how many years he would be banned if he had hit an official with a ball, after 17-time Grand Slam winner Novak Djokovic's default at the US Open.

The Australian has waged a running battle with the Serb in recent months over his ill-fated Adria Tour exhibition series,...