Ole Gunnar Solskjaer felt his Manchester United players "didn't turn up" on the big stage as his team slipped to a Europa League final defeat to Villarreal.
David de Gea's missed penalty consigned United to a dramatic 11-10 penalty shootout defeat against Unai Emery's side in the Europa League final following a 1-1 draw in Gdansk.
United had just two shots on target in the match as extra time failed to illuminate a poor contest, but Geronimo Rulli would prove the hero during a pulsating shootout, first converting his own penalty before keeping out De Gea's effort as Unai Emery clinched a fourth Europa League title.
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This felt a huge missed opportunity for Solskjaer as his quest for a first trophy as Manchester United manager goes on.
"We didn't turn up," he told BT Sport.
"We didn't play as well as we can do. We started alright and they scored from their only shot on target but it was disappointing to concede a goal on a set play. We pushed and pressed and got the goal. But after we scored we couldn't control the game and dominate the way which we wanted.
"They made it hard for us by closing the spaces. We had the majority of the possession and they defended well. We didn't create enough big chances.
"Now isn't the time to put the finger on what I would have done differently but when you don't come away with the trophy you've not done everything right.
"We are getting closer and closer [to winning titles] we were one kick away today from having a trophy. But we've got to have the desire to come back next year and improve. The only way to get the margins in your side is to work harder and better."
When asked in his post-match press conference if it's been a successful season for Manchester United, he replied "No."
"We need to get better, simple as. We've done really well this season to come through a difficult start and no pre-season, losing three of the first six games. We pushed in the league and got closer to the top than we thought at that point. And we got to a final but you need to win these finals to make it a good season."
"We, who are here now, need to do better, work better, harder, cleverer. But two or three players to strengthen the starting XI and the squad altogether is important for us to go even further. I'm sure our challengers will also want to improve, so we'll improve as much as we can."
Asked why he took 100 minutes to make his first substitution, Solskjaer said: "We felt the players out there, Mason, Marcus, Bruno, Edi, match-winners, can create anything. Scott, who I thought was the best player on the pitch, and Paul, so it's difficult to make that change, especially when Fred has been injured for a week. We just couldn't create enough chances to win the game.
"We didn't do enough in the 120 minutes to score more goals. That's the disappointing bit.
"You've got players of high quality there, and we started with loads of goal scorers, match-winners, and hoped it would give us the upper hand.
"That disappointment is the worst feeling, these are the moments you remember most in your career, as a player and as a manager.
"You can go on your holiday and do nothing about it, or go home and do something about it, and come back even better, hungrier, stronger, and be better from the first minute.
Rashford hits back at United's critics
Marcus Rashford played all 120 minutes of the match in Gdansk but had one of his quieter games.
When asked what the feeling was like in the dressing room having watched Villarreal lift the trophy, he told BT Sport: "Disappointing, in one word.
"The feeling inside is difficult to explain. We came here to win, we've been working hard all season, and this was the opportunity to win a trophy. It didn't happen for whatever reasons.
"Maybe not now, we have to get rid of the disappointment, but after that we have to look at the game and where we can improve, what went wrong.
"The team will not give up. There is no chance. The manager will not give up. He won't allow us to give up. We will come next season with a bigger desire.
"The club, Manchester United, people say a lot about Manchester United, that they're going downhill, blah, blah, blah, blah, blah... but for me, the club, the desire, the hunger, the talent, the ability, the squad, we have everything to compete at the highest level.
"We just have to show it to the world, show it to ourselves. Show why we belong in the top places, why we belong in finals, and why we need to be winning finals.
"In the league we finished second, it doesn't count for nothing. For us, second is nothing. I don't want to hear: 'Oh, they were so close' It doesn't mean anything. There is one winner and one loser.
"To win big trophies you have to show sacrifice. I could walk you into the dressing room and show five, six players, and me as well, we have had injuries since the beginning of September, and we all stay together as a unit to fight and be successful for the club. We have to go away now and clear our heads. When we come back we start fresh.
"The players believe in the process, and this isn't the end of the process. Part of the process is to have ups and downs. And we've had plenty every season.
"I promise you, I promise the fans, we don't give up. There's no chance. We come next season with more desire and more hunger.
"Sacrifice means a lot, I know in every club they don't have this sacrifice. In the top clubs, they have. This is why the top clubs win the trophies.
"We are close, I promise we are close. But close is not good enough, we have to be there."
McClaren: Ole put all his eggs in one basket
Former Manchester United assistant manager Steve McClaren told Sky Sports:
"I feel there were three key elements to the game which decided it. Unai Emery won the tactical battle with a very compact 4-4-2 and he used his subs all the way through the game so they finished extra time stronger.
"The second thing was that Ole put all his eggs in one basket. All his best players were on the field to begin with. After 95 minutes plus extra time, he had nowhere to go. He nothing on the bench really to change anything. Usually he has Rashford on the bench, or Pogba or Greenwood but he didn't have any of them who could change the game so they ran out of energy.
"They didn't use enough subs but the third and most important thing was that they didn't show up, as Ole said. The big players didn't turn up. Harry Maguire wasn't there, and both Lindelof and Bailly were at fault for the first goal. The key for me was that Fernandes, Rashford and Greenwood didn't turn up. It was a game I expected Manchester United to win so it's a huge disappointment."
What's next? Euros, transfer window, 2021/22 key dates
Euro 2020 kicks off on Friday June 11 - just 19 days after the conclusion of the 2020/21 Premier League season - and runs until Sunday July 11.
The 2021/22 Premier League campaign will start on the weekend of Saturday August 14 - 34 days after that Euro 2020 final at Wembley.
Clubs will be able to start planning for the new term when the top-flight fixtures are released at 9am on Wednesday, June 16 but transfer business can start in earnest before then, with the summer transfer window opening on Wednesday June 9.
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The 2021/22 Championship season begins a week before the top-flight one on the weekend of Saturday August 7. All Sky Bet EFL fixtures will be announced at 9am on Thursday June 24.