Great Britain face an uphill task if they are to earn a World Group playoff tie later in 2013 after falling 2-0 behind to Russia in the Davis Cup.
Both Dan Evans and James Ward impressed against their higher-ranked opponents at the Ricoh Arena, but they each succumbed to five-set defeats.
Evans twice came from behind against Dmitry Tursunov to force a decider, but the world number 67 finally prevailed 6-4 6-7 6-4 5-7 6-4.
Ward had looked on course to level up proceedings after moving two sets ahead, but Evgeny Donskoy fought back to win 4-6 4-6 7-5 6-2 8-6.
Great Britain's hopes in the tie now rest on Saturday's doubles, with Jonny Marray and Colin Fleming requiring a victory to maintain their team's interest in the match.