Australia trails Kazakhstan 2-0 in the Davis Cup quarter-final in Darwin after Thanasi Kokkinakis and Nick Kyrgios were both beaten in the opening singles.
Nick Kyrgios lost in four sets to Aleksandr Nedovyesov, 6-7 (7/5), 7-6 (7/2), 6-7 (7/5), 6-4, in the upset result of the day to leave Australia one loss away from being out of the Cup for 2015.
Kokkinakis had lost in straight sets to Mikhail Kukushkin in the opening rubber, 6-4, 6-3, 6-3.
Kygios found it difficult to break the serve of Nedovyesov - who is ranked number 115 in the world - and the first set went to a tie-break, which the Kazakh player won 7-5.
The struggle continued in the second set, which also went to a tie-breaker - this time Kyrgios prevailed, 7-2.
The Australian finally managed to break Nedovyesov's serve in the third set, but his opponent also broke Kyrgios once to set up a third tie-breaker in a row.
Once again, the Kazakh player won 7-5, to take a two sets to one lead.
Nedovyesov broke again for 3-2 in the fourth set, and consolidated the break.
He held for 5-3, then Kyrgios - serving to stay in the match - held to love.
Kyrgios hit a great forehand winner for 15-15 in the tenth game, but Nedovyesov was not to be denied, and he served out to clinch the match in two hours 36 minutes.