Darren Fletcher felt Bayern Munich's players 'pressured' referee Nicola Rizzoli into sending off Manchester United full-back Rafael.
United crashed out of the UEFA Champions League on away goals despite beating Bayern 3-2 at Old Trafford in the second leg of their quarter-final tie.
A Nani brace, following Darron Gibson's early opener, had given United a 3-0 lead before Ivica Olic pulled a goal back for Bayern just before half-time.
Bayern's cause was helped further when Rafael was dismissed early in the second half after collecting a second yellow card for pulling back Franck Ribery.
Arjen Robben then struck a stunning, and decisive, goal for Bayern to ensure Louis van Gaal's side went through on away goals after a 4-4 aggregate scoreline.
However, while acknowledging Rafael will learn from his red card, Fletcher believes the official was not going to send off the Brazilian until the visitors protested.
"He was pressured into giving it by the Bayern Munich players, everyone can see that," Fletcher told Sky Sports.
"He decided he wasn't going to give it, then he was pressured into it.
"He's (Rafael) young and he'll learn from it. He's got a great future ahead of him and he's going to be a great player and a big asset for Manchester United.
"He'll bounce back, he's a strong character."
In addition to the red card, midfielder Fletcher felt Olic's goal two minutes before the interval was another key moment in a pulsating second leg.
He added: "I think it was a really massive point for them in the game. If you're going in 3-0 up you're well on your way.
"It was a bit of a scrappy goal, but even from that situation we felt comfortable and we felt as if there would be more goals.
"Then the red card makes it really difficult. They passed the ball well, they kept it well and we really found it difficult to create chances after that."