The Scotland international has stepped up his game this season after an outstanding campaign last term.
Fletcher told manutd.com: "I'm enjoying everything at the moment because the team is successful. Last season was great, despite the disappointment of the Champions League final. That low was partly because it was the last game as well, but if you look back on what we achieved right throughout the season it was fantastic. I played in a lot of big games and was given a consistent run in the side. The most important thing for me this season has been to kick on and not sit back and take my place for granted.
"At United you're proving your worth in every game, there's always someone who wants to take your shirt. That drives you on. I want to keep improving as a player, as I feel I have done in every season I've been here. You look at Giggsy, Scholesy and Gary Neville - as they've got older they've improved through their experience, knowledge, maturity and application of what they do off the pitch as much as on it."