Manchester United defender Rafael says he has learnt his lesson from his red card against Bayern Munich four years ago.
The Brazilian right-back was given his marching orders in the 2009/10 version of the UEFA Champions League early in the second half of the quarter-final second leg at Old Trafford when the Red Devils were 3-0 ahead.
Rafael's dismissal allowed Bayern back in the contest which finished 3-2 and sent the Bavarians through to the semi-finals on away goals.
Ahead of Tuesday night's quarter-final first leg between United and the reigning European champions, Rafael has made it clear that he will not find himself in a similar situation that would endanger the club.
"I have learned from that," he said.
"I will never forget that. I played so good in the first half but then I got sent off like I did so it's just learning.
"It's good learning curve for me. It cost United the match. It was a lot of help for Bayern when they play against 10 men."
Rafael added that the European competition is something United can focus on after a tough season in the Premier League.
"Now we can focus on the Champions League. It's a very important tournament for us," he added.
"Everyone knows it's hard that's why I am saying we have to play with real quality. We have to show everyone what we are capable of and get a good result."
