The World No.9 caps a memorable year with a special moment.
Several categories offer tight reaces with the results due out in early December.
The Czech also adds Olga Savchuk to her team.
ATP Finals champion joins three of world's Top 5 in field.
Days after his father died, Roberto Bautista Agut helped lead Spain to its sixth Davis Cup championship.
The American joins a star-studded field in New Zealand.
Novak Djokovic advocates a change to new Davis Cup Finals.
