Nick Kyrgios doesn't fear any tennis player due to the simple fact that's he's played and defeated the majority of them as he revealed in a recent A and A.
Kyrgios is not playing tennis at the moment due to a knee injury but when he is playing he's a crowd magnet and a pretty strong player. He proved it last year with some incredible results overall. He's always had that talent and over the years he earned some huge wins over some incredible players.
During his Q and A Kyrgios was asked how he deals with fear on the court and if he's afraid of some players. His response was:
"I don't fear any tennis player. Beaten them all pretty much."
His attitude in matches certainly speaks to that but even he can get nervous at times against some of the best which the Wimbledon final against Djokovic demonstrated.