Eric Abidal believes Barcelona's collapse against Liverpool last season was coming after the La Liga side failed to heed the "clear warning" of the first leg.
Despite a creditable performance from the visitors, Barca beat Jurgen Klopp's men 3-0 in the first leg of their Champions League semi-final on May 1 after Lionel Messi had added a brace to Luis Suarez's opener at Camp Nou.
However, the return game at Anfield saw Liverpool run out 4-0 winners as they produced one of the most remarkable comebacks in European history on May 8 to book their place in the Madrid final.
The Reds would go on to lift their sixth European Cup with a 2-0 win over Tottenham in the Wanda Metropolitano and Barcelona have largely struggled since that incredible night on Merseyside over six months ago.
Abidal, who now works as the club's director of football, believes his club were undone by ignoring the first-leg performance of Klopp's side in Barcelona.
"I will speak about the first leg first," Abidal told Sport. "All Barca fans will surely remember more the result of that game.
"It was really difficult and the final result is not reflective of the game. It was a clear warning of what could happen.
"The disaster at Anfield was down to the attitude of the team and [not scoring] a goal. We lacked a goal. With one goal, no one would remember [the game in] Liverpool. That's what I had in my mind in the stands. It had to happen."
The semi-final defeat to the Reds was Barca's second successive collapse in the Champions League knockout stages after they were dumped out by Roma in the quarter-finals the year previous.
After a 4-1 win from the first leg, Roma beat the Catalans 3-0 in Italy to go through on away goals but Abidal does not think the two results can be compared.
"It was a different accident to Roma," said the Frenchman. "They're not equal rivals and the games weren't the same. Liverpool was not Roma.
"You learn from it, but you have to think that the difference was one goal. And that one goal marked the season.
"[The responsibility for the result] is joint between the players and the coach. It was an accident. Things happen in football that you can't explain. Not even the players that were playing the game."