Valencia coach Gary Neville admitted to the biggest disappointment of his time in La Liga after Sunday's 3-1 home defeat to Atletico Madrid.
The game at Mestalla was evenly balanced at the break after first-half goals from Antoine Griezmann for the visitors and Denis Cheryshev for the home side.
But Atletico took control after the break with substitutes Fernando Torres and Yannick Carrasco both scoring, and Valencia being reduced to 10 men when centre-back Aderlan Santos picked up his second yellow card.
The former Manchester United defender told his postmatch news conference he felt his team could have won the game against one of Europe's top teams, but just like a week ago at home to Athletic Bilbao they were beaten by sucker-punches late in the game.
"I think the second half we played well, until the [Torres] goal going in changed the course of the game," Neville said. "The moment went against us tonight and from there the game became difficult. For 25 minutes we played well and it was an even game. We're playing against one of the best teams in Europe tonight by the way.
"For 70 minutes we gave them one of the hardest games they've had. The second goal and the sending off changed the game, that was my assessment of it. I'm disappointed, probably the most disappointed I've been after a game. I don't like to repeat mistakes -- like last week -- and it feels the same. I felt we could have got something out of the game."
When Santos was sent off with 10 minutes remaining, Neville asked another defender in Aymen Abdennour to get ready. However centre-forward Alvaro Negredo was eventually sent on after Mestalla fans had loudly chanted the attacker's name, and seconds later an over-stretched Valencia defence conceded the killer goal to Carrasco.
Asked if he had been swayed by the crowd's reaction, Neville said it had actually been his assistants who had persuaded him to change his mind, and suggested he now felt he should have stuck to his own first idea.
"Alvaro was coming on, then Santos was sent off so I said to Abdennour, get changed you're coming on," Neville said. "My staff called me back, they said let's gamble, go with three at the back. We decided to gamble and we changed our mind again. We decided with the coaching staff, it definitely wasn't the fans. From my point of view, maybe sticking with the original decision might have been right."
With 10 La Liga games remaining, Valencia sit eight points off European qualification and eight points off relegation, meaning their main hope for excitement this season rests with the Europa League.
Neville will also face Injury problems ahead of Thursday's Europa League last-16 first leg at Athletic Bilbao, after midfielders Cheryshev and Enzo Perez both came off with issues.
"Denis Cheryshev had a muscle injury," Neville said. "He had to come off. I wouldn't have substituted him if not. Enzo had a problem too."