World number two Daniil Medvedev beat Marin Cilic to lead the Russian Tennis Federation to a third Davis Cup title.
Andrey Rublev had won the first singles match against Borna Gojo 6-4 7-6 (7-5) to put the Russians ahead in Madrid.
Medvedev did not drop a set at the tournament in a year where he won his maiden Grand Slam title at the US Open.
“It feels amazing but I am more happy for the team than for myself,” the 25-year-old said in his on-court interview.
“It is never easy to come at the end of the season but it was the best two weeks of my career.”
Medvedev was also part of the team who won the ATP Cup at the start of the season.
The Russians are the fourth nation to win both the Davis Cup and Billie Jean King Cup – the women’s equivalent team competition – in the same year.