Athletic Bilbao coach Marcelo Bielsa has said the club's fans were within their rights to whistle his decisions after Thursday night's 3-2 home defeat to Olympique Lyon left last season's Europa League finalists on the brink of a group stage exit.
Athletic have just one point from their first four Group I games, and need to win their last two matches - and hope Sparta Prague lose at home to already-qualified Lyon - to have any chance of progressing.
Fans inside San Mames, who saw Bielsa's side motor to home wins over Manchester United, Paris St Germain and Schalke last season, reacted with loud whistles when the Argentine coach substituted top scorer Aritz Aduriz and young attacker Iker Muniain as Athletic tried to get find a late equaliser.
Bielsa told reporters after the game that he had understood the message delivered by the supporters.
"The public said that the decisions I took were not right, and I cannot say whether they were right or whether it was me who acted correctly," he said.
"I cannot say that I am infallible in the decisions I take."
Athletic were 2-0 down at half-time after goals from Bafetimbi Gomis and Yoann Gourcuff, but drew level within 11 minutes of the restart through Ander Herrera and an Aduriz penalty.
Lyon's third goal, from Alexandre Lacazette, knocked the stuffing out of the Basque side, as Bielsa admitted. "It was one game until the scoreboard became 3-2 - until then, it seemed to me that our contribution was satisfactory," he said.
"After the equaliser, we were looking to kill the game. The third goal was very decisive for the final result."
The former Argentina and Chile national coach argued that individual mistakes had once again cost his side, with goalkeeper Gorka Iraizoz palming the ball straight to Gourcuff for Lyon's second goal and Muniain gifting possession to Gueida Fofana in the run-up to Lacazette's winner.
"When these types of situations keep happening during the season, we realise we must be less generous," Bielsa said. "All the mistakes we make [are not helping], but I cannot say that the team's problems do not have a solution.
"The only path is to observe the errors, analyse them and draw conclusions so that we can work towards them not happening again."