Several veterans in the Barcelona team have seen the side slide from the top of the game to the Europa League.
Barcelona's fall from grace was described by a Spanish newspaper as their "resignation from the football elite".
Busquets said that they feel bad. We're in a tough situation. We got ourselves into this mess and it hurts a lot.
The last time they were not in the knockout stages was in 2003-04. They were eliminated by Celtic.
In 2000, they failed to qualify for the group stage of the competition for the first time. Since then, Barcelona have won the tournament four times.
Barcelona staged their resignation from the football elite in a display of all their weaknesses when they fell without complaint against a team that was in third gear and without giving the feeling of wanting to humiliate them.
They are going into the knockout round play-off. The winner of that game will play the group winners in the last 16.
Steve McManaman, a former Real Madrid player, thinks that demotion to the Europa League might be a good thing as it would mean they would be in the playoffs next season.
They are currently seventh in La Liga and have a new coach.
Ronald Araujo, a defender for Barcelona, told Movistar that it was a damning result.
Araujo was one of four central defenders who played the final hour in the back four.
We didn't not qualify because of this game, but because of what we did in the other games.
Two goals were scored against rock bottom Dynamo Kyiv in the other games.
Araujo said that they are not among the best teams in Europe.
We would have qualified if we were. We want to win the Europa League. We have to go out and try to win it.
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How bad are Barcelona?
Lionel Messi has scored five goals for Paris Saint-Germain this season, whileAntoine Griezmann has four for Atlante Madrid.
Barcelona's squad is made up of players who wouldn't have fit in with the great teams of the past.
They lost their all-time top scorer Lionel Messi and several other first-team players in the summer as part of a financial crisis.
Joe Cole said that there are three players who would want to keep hold of them. They can't compete with the group of players.
Their seventh defeat of the season was this one. They are 16 points behind Real Madrid.
Pete said that people didn't believe in the miracle that was needed.
The best teams in Europe and Barcelona are not always the same. I don't think a lot of their supporters think they can win the Europa League.
There are some serious issues that they have to deal with, and they have financial implications to deal with as well.
They won't talk about it, but they were failing two or three seasons ago, and it was Messi who kept them afloat.
The headline was 'Europa League embarrassment'.
"Barca is trapped in time." The nightmare began after a 2-8 start in Lisbon, and continued after being demoted to the Europa League.
There are any signs of promise?
Barcelona has been taken over by Xavi.
If Barcelona are to reach the elite again, they need to add to their quality.
The three senior Spain internationals are Gavi, Ansu Fati and Pedri. Pedri was named the best young player of the year by France Football.
Since they hired Xavi, a former captain, from Al Sadd, there have been some promising signs.
After five games, it's clear that Xavi has some of the characteristics of his boss.
He has a clear vision and charisma. If you don't have the players, you can't put that into action.
"They've got the right man in charge," Peter said. He knows how the youth academy works.
Their future is youth because they don't have enough money to buy players like they have. They need to build from young players.
"They have some good ones but it's not going to be a quick process - it could be five years."
