Manchester United have been home to some of the top talents in world football, but a few unsung heroes didn't receive their due recognition.While big-money and big-name signings often hog all the attention, it is the hard-working players operating relentlessly out of the limelight that form the engine-room of elite teams like Manchester United. These players have no qualms doing the 'dirty work' to keep the team ticking.Five Manchester United players who have flown under the radar this century:Manchester United's legendary manager Sir Alex Ferguson had some of the game's top talents at his disposal. But his squads were built around players of the likes of Paul Scholes, Roy Keane and Dennis Irwin, among others. These players earned an enormous reputation and recognition for the vital roles they played for United while lsrgely operating under the radar. On that note, let’s take a look at the five most underrated Manchester United players since the turn of the century.#5 Daley BlindDaley BlindDaley Blind was brought in by his compatriot Loius van Gaal at Manchester United, where he started off as a holding midfielder.When he left Manchester United to return home to Ajax, he transitioned into a left-back. That’s just one of many roles Blind played for Manchester United during his four-season stay at the club, as he was vital in addressing his team's defensive fragilities.The Dutchman was first transformed into a centre-back under Van Gaal, owing to the unreliable defensive pairings and injuries at the back. It was thought that Blind would not be able to cope with the physical requirements in a central defensive role.But he remains one of Manchester United’s finest central defenders in the post-Ferguson era of signings. Blind brought his immense technical ability, along with precise passing and a calm presence in defence, to the fore.First of all I want to say how proud I am to be a part of the Manchester United family. To play for the biggest club in the world with such a history meant a lot to me. I had 4 great years with 4 trophy’s! (1/3) pic.twitter.com/6mUkmN4DTP— Daley Blind (@BlindDaley) July 17, 2018Under Jose Mourinho, the now-31-year-old got converted into a left-back and excelled in that role as well. Whenever Manchester United were plagued by a lengthy injury list or absence of first-team regulars at a particular position, Blind would always step in and do the needful.Now at Ajax, Blind played a crucial role in the Eredivisie club's dream run to Champions League semi-finals in 2019.#4 John O’SheaJohn O'SheaMuch like Daley Blind, John O'Shea donned many hats for Manchester United, showcasing his immense versatility to pull off all the roles. O'Shea got promoted to the Manchester United first team from their academy in 2001-02.Versatile players like O’Shea and Blind are a manager’s dream. But their vital contributions are often overlooked; they are seen as bit-part players and never get the chance to establish themselves in their preferred positions. However, O’Shea did not put a foot wrong at Manchester United and was one of Sir Alex Ferguson's most trusted players.The now-39-year-old, however, never received the recognition he deserved from fans as well as the club. That was despite O'Shea making 394 appearances for Manchester United while operating in midfield and virtually any position across the back four.Speaking of memories...*John O'Shea once did a nutmeg against Real Madrid in the @ChampionsLeague, pass it on* pic.twitter.com/jFkRk1mDSO— Manchester United (@ManUtd) April 30, 2019O’Shea won a Champions League and five Premier League trophies in a glorious decade-long stint at Manchester United.