Team Europe made it back-to-back Laver Cup titles thanks to wins by Roger Federer and Alexander Zverev.
Martin Klizan inflicted a semifinal defeat on Stan Wawrinka in St. Petersburg and will take on top seed Dominic Thiem in the final.
Dominic Thiem said he was lucky to beat Daniil Medvedev in his homeland to reach the last four in St. Petersburg.
Changes to the format of the Davis Cup have been approved by the ITF board, with an AGM set to determine whether they will be introduced.
The draw for the Davis Cup World Group play-offs has been held, with top seeds Argentina up against Kazakhstan.
The Australian bad boy is one of the great sporting enigmas, but an on-song Nick Kyrgios is a force to be reckoned with, according to Jim Courier.
Great Britain will have to cope without Andy Murray when they face France in the Davis Cup. "It's obviously a big loss," said Leon Smith.
The Davis Cup could be altered to a best-of-three-sets format, but Rafael Nadal believes those changes do not go far enough.