The Brazilian has been a key member of Sir Alex Ferguson 's side this term, making 31 appearances in all competitions, with only Michael Carrick and Patrice Evra featuring more often.
And when asked by MUTV if this is his best season yet at United, the defender responded: "I think so. I have played many games very consistently so it is probably my best season here.
"Of course, I think there are some games where I feel I could have done more - I should have done this or should have done that better. I definitely still want to improve."
Despite not playing every match, the defender believes he learns valuable information just by watching from the sidelines.
"I am just rested sometimes," he added.
"We have to rest so I'm happy because we won [against Reading last Monday] to stay in the FA Cup.
"I always want to play. I think every player wants to play in every single game but, when you're not playing, you can learn from things. I was there watching and can learn a lot.
"I think because it was a big game [against Real Madrid], I expected a lot more of myself and I thought I had to win every ball. I think I came out for the first half thinking like that. I thought, 'I need to win this ball' and, if I did something wrong, then I really had to win the next ball.
"At half-time, the boss came to speak to me and I realised: 'Come on, it's the same as it has been all season. I don't have to win every ball.' So I think I did better in the second half."