A defiant Nuno Espirito Santo insists Valencia will still make the Champions League knockout stage despite their defeat to Zenit on Tuesday.
Goals from Oleg Shatov and Artem Dzyuba secured the Russian champions' fifth win from five matches in Group H and means Valencia will face a tense final game at home to Lyon in the race to join them in the last 16.
Nuno has faced increasing pressure as a result of his side's mixed performances this season but he is adamant they will still progress in Europe, describing the showdown at the Mestalla on December 9 as "a final".
"We competed but they penalised the mistake that we made. In the second half we had chances, the first especially, but we faced a team who took advantage of their chances and our mistakes," he said afterwards.
"I'm convinced that, at the Mestalla, we're not going to fail."
Nuno opted to introduce Santi Mina in the second half as Valencia chased the game but a red card for Ruben Vezo in the 80th minute effectively brought their fightback to an end.
"I introduced that change [Mina] to bring some fresh air, but after the red card it was decided. I'm satisfied with the attitude of the players," Nuno said.
Valencia handed a surprise debut to 18-year-old Rafa Mir in St Petersburg and Nuno believes the attacker has a bright future ahead of him.
"He's is a very interesting player. He has quality and a promising future. He's integrated with us and he's one more option that we have," the coach added.