Novak Djokovic is the reigning Australian Open and Wimbledon champion
Djokovic has not lost a match at the event, although he has dropped sets in his past two matches against Medvedev and Canada’s Denis Shapovalov.
However, he was able to overcome the highly-rated Medvedev to seal Serbia’s place in the final after Dusan Lajovic had beaten world number 17 Karen Khachanov 7-5 7-6 (7-1).
Viktor Troicki and Nikola Cacic then made it a clean sweep in the doubles with a 6-4 7-6 (9-7) win over Teimuraz Gabashvili and Konstantin Kravchuk.
“Medvedev is one of the best players in the world and he showed today why,” Djokovic said after their rubber.
“This was the most difficult challenge I have had so far this year.”
The 16-time Grand Slam champion later withdrew from the ATP event in Adelaide, which begins on 12 January. The Australian Open – the first Grand Slam of the year – starts on 20 January.
The 24-nation event started with six groups of four teams, who each played three round-robin ties. The ties – comprising two singles matches and one doubles – are best of three.