Paris—Novak Djokovic and Nikola Cacic lost a dramatic deciding tie-break in their doubles rubber as Serbia suffered a shock defeat by Germany in the Davis Cup Finals, while Daniil Medvedev helped the Russian Tennis Federation to an opening win.
World number one Djokovic had drawn Serbia level in their second group-stage tie by beating Jan-Lennard Struff after Filip Krajinovic’s loss to Dominik Koepfer.
But the 20-time Grand Slam singles champion and Cacic slipped to a 7-6 (7/5), 3-6, 7-6 (7/5) defeat by Kevin Krawietz and Tim Puetz, who got over the line on their third match point in Innsbruck.
The matches in Austria are being played behind closed doors due to new coronavirus restrictions in the country.
Germany will qualify for the quarter-finals from Group F if they can beat Austria on Sunday, which would leave Serbia waiting to see if they progress as one of the two best runners-up.
Djokovic is hoping to cap a brilliant season, which saw him only miss out on a calendar Grand Slam with defeat by Medvedev in the US Open final, by helping his country win the Davis Cup for the first time since 2010.
The Russians, among the title favourites, made a perfect start to their campaign with a 3-0 victory over Ecuador.
World number five Andrey Rublev overcame a second-set blip against 291st-ranked Roberto Quiroz to win 6-3, 4-6, 6-1 in the opening rubber in Madrid.