Manchester United boss Ole Gunnar Solskjaer said he should possibly have substituted Fred before the Brazilian was sent off in the 3-1 Champions League defeatby Paris St-Germain.
The midfielder was shown a second yellow card in the 70th minute for a foul on Ander Herrera, having been booked in the first half for a head-to-head clash with Leandro Paredes.
“He was lucky to stay on,” said Solskjaer of the first incident. “The referee made a mistake there but that’s allowed.”
The manager, who lost goalscorer Marcus Rashford to a shoulder injury during the game, said he spoke with Fred at half-time and decided then to keep him on based on his first-half performance.
“He played well but with the decision the referee made you maybe look back and say you should have (taken him off),” Solskjaer added.
“But there was no reason from his performance to take him off.”
Solskjaer did not think the foul on Herrera warranted a second yellow card, adding: “It was not a foul. Fred was disciplined in the second half. I asked him to be sensible and he was.”
The defeat leaves United level with PSG and RB Leipzig on nine points in Group H and knowing they need a draw away to the German side next Tuesday to reach the last 16.
“We know the destiny is in our own hands,” said Solskjaer.
“We know that we play against a good team in Leipzig, who were in the semi-final last year, but we are developing into a better team as well.
“I was very pleased with the performance (against PSG) apart from of course they were more clinical. Big games most of the time are decided by fine margins and this time they were against us.”
BBC Radio 5 Live pundit Chris Sutton felt keeping Fred on was a decision that ultimately cost Manchester United the game.
“I think Solskjaer made a massive error,” he said. “Anything Fred did in the second half they (PSG’s players) were going to be all over the referee.
“It was really poor decision from Fred but an even worse decision from Solskjaer because that ultimately cost them the game.”
Former Crystal Palace striker Clinton Morrison added: “You’ve got Neymar in (the referee’s) ear at half-time and Fred makes it easy for the referee. Solskjaer could’ve made changes.”