World No. 1 leads Spain past Russia, offers reaction to new Davis Cup format.
Washington state will host its first Fed Cup tie in February.
Former No. 1 says he's rooting for success in World Cup-style Davis Cup Finals.
Grand Slam king sees 2020 as a a year of major breakthrough with a big caveat.
Dominic Thiem on why ATP Finals champion Stefaos Tsitsipas is impact player.
Alexander Zverev says we will see a new Grand Slam champion in 2020.
Grand Slam king cites four priorities for a successful 2020.
