Serbia in danger of Davis Cup Finals exit
Favourites Russia have opened their Davis Cup Finals campaign with a resounding victory over Ecuador but Serbia's defence of their title has suffered a major setback.
Great Britain began with a win against France and Italy eased into the quarter-finals by defeating Colombia.
However, 28-time champions Australia are facing almost certain elimination despite beating Hungary 2-1.
Novak Djokovic's Serbia were beaten 2-1 by Germany in Group F as the world number No.1 and Nikola Cacic lost a thrilling doubles decider 7-6 (7-5) 3-6 &-6 (7-5) to Kevin Krawietz and Tim Puetz.
The result means Serbia will have to wait until Sunday's final round-robin matches before knowing whether they progress to the quarter-finals or not.
In the singles, Dominik Koepfer defeated Filip Krajinovic 7-6 (7-4) 6-4 before Djokovic replied with a 6-2 4-6 defeat of Jan-Leonard Struff.
The Russians beat Ecuador 3-0 in Madrid to move level with holders Spain whom they face on Sunday to decide who will emerge as winners of Group A.
World No.5 Andrey Rublev beat Roberto Quiroz 6-3 4-6 6-1 before US Open champion Daniil Medvedev crushed Emilio Gomez 6-0 6-2.
Rublev then teamed up with Aslan Karatsev to beat Gonzalo Escobar and Diego Hidalgo in three sets.
Italy, who beat the US in their opening Group E tie, won both their singles matches against Colombia in Turin with victories for Lorenzo Sonego and Jannik Sinner.
Britain were given a fast start against France in Group C with Dan Evans beating Adrian Mannarino 7-5 6-4 and Cameron Norrie defeating Arthur Rinderknech 6-2 7-6 (10-8).
France, who beaten the Czech Republic in theoir opening tie, won the doubles against the Brits in what could prove vital in the hunt for a spot in the last eight.
Australia beat Hungary 2-1 in Turin but finished their Group D campaign with a 2-4 record having lost 3-0 loss to Croatia in their opening match on Thursday.
John Millman was stunned 4-6 6-4 6-3 by world No.282 Zsombor Piros before Alex de Minaur overcame Marton Fucsovics 7-5 2-6 7-6 (7-2).
The doubles pairing of Alex Bolt and John Peers sealed the tie when they beat the Hungarian duo 6-3 6-7 (11-13) 6-3.
In Madrid, Kazakhstan beat Sweden 2-1 in Group B with their doubles pairing of Andrey Golubev and Aleksandr Nedovyesov sealing victory after Swede Elias Ymer and Kazakh Alexander Bublik won their singles rubbers.
Sweden remain top of the group, having beaten Canada 3-0, but Kazakhstan can win it with a victory over the Canadians on Sunday.
Eighteen teams are competing in six round-robin groups across three European cities - Madrid, Innsbruck and Turin - for places in the quarter-finals, with the six group winners and the two best runners-up advancing.
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