Smalling, who joined United from Fulham in 2010, feels that he has improved on and off the pitch.
"I've improved technically since coming here but also in attitude," Smailling told The Telegraph.
"At this club it's always drilled into me 'Make sure you're a winner, go about off the pitch like you're a winner.' It helps when you have players like Giggsy and Rio who have won a lot. That really drives you on.
"It doesn't matter whether it's the 93rd minute, Giggsy is making his mazy runs. You could forgive him for not coming into training everyday, because he's done so much in the game, but everyday he's out there. He doesn't seem to need a rest."
United's next game is against Norwich City this afternoon.