Manchester United are the most successful team in the Premier League era. They have won 13 Premier League titles, five FA Cups and two UEFA Champions League titles since the rebranding of the league. The club enjoyed their most successful period under Scotsman Sir Alex Ferguson between 1992 and 2013.Ferguson was known to set up his Manchester United team to play simple but effective football. He preferred a 4-4-2 system and played with that for almost the entirety of his managerial career. Under Ferguson, players like Eric Cantona, Roy Keane, Ryan Giggs, Wayne Rooney, Cristiano Ronaldo and Ruud van Nistelrooy enjoyed prolific spells.Rooney is United and England's all-time top scorer with 253 and 53 goals, respectively. The striker won 16 trophies with United.Statman Dave@StatmanDaveWayne Rooney’s Man Utd career by numbers: 👕 559 appearances ⚽️ 253 goals 🏆 16 trophies What an unbelievable career. 🙌8:09 AM · Jan 15, 2021115211182Wayne Rooney’s Man Utd career by numbers: 👕 559 appearances ⚽️ 253 goals 🏆 16 trophies What an unbelievable career. 🙌 https://t.co/RNWSXQoZb1However, the great Manchester United teams of the past, too, have had players who are often overlooked. These players often played fewer minutes than the main stars, but were key to the club's rise to the top of English football.Without further ado, here's a look at the five most underrated Manchester United players of the Premier League era:#5 John O'SheaJohn O'Shea enjoyed a highly-successful spell at Manchester United.John O'Shea was born in Waterford, Ireland, in 1981. The Irishman was a Manchester United academy product, and came through the ranks at Carrington. He made his senior for the Red Devils in 1999. O'Shea also played for Sunderland for eight years between 2011 and 18, and a season at Reading after that.He was known for his efficient style of play that often went under the radar. He wasn't the quickest player, but used his physique effectively to protect the ball and contest aerial duels. The former Manchester United man was also a very versatile player. He played across all four defensive positions in a back four throughout his club career.Although a defender, O'Shea also scored clutch goals; he once did so in an away game against United's fierce rivals Liverpool. The Irishman scored in the last minute to hand United a win on the night.Man Utd Fans Bantz@ManUtdFanBantzEnjoy your retirement in the summer, John O’Shea. Who could forget this last minute goal vs Liverpool?1:52 AM · Mar 30, 201811Enjoy your retirement in the summer, John O’Shea. Who could forget this last minute goal vs Liverpool? https://t.co/PEJ2PyEJxSJohn O'Shea made a total of 394 appearances for Manchester United, scoring 15 goals and assisting 23.With the Red Devils, O'Shea won five Premier League titles, one FA Cup, one FIFA Club World Cup and one UEFA Champions League title. He also represented the Republic of Ireland 118 times, and ranks third in their all-time appearances list.#4 Darren FletcherDarren Fletcher celebrating a goal for Manchester United.Darren Fletcher was born in Dalkeith, Scotland, in 1984. He, too, came through the ranks at Manchester United's academy in Carrington. Fletcher made his senior debut for the club in 2003, and enjoyed 12 successful years in Manchester. He later represented West Bromwich Albion and Stoke City for short spells.Fletcher was usually deployed in a box-to-box role in midfield - one he excelled at. The Scotsman was known for his tenacity, grit and determination. He was an energetic presence in United's midfield, and rarely seemed to tire. Fletcher was an extremely versatile player, and played in various position,s including as a full-back, winger and centre-back.He also scored some important goals during his United career, netting a brace in a stunning 4-3 win over arch-rivals Manchester City in 2009.You can watch the full match highlights here:Elijah Kyama@ElijahKyamaRemember Man United 4-3 Man City ?Ben Foster vs Tevez at CityDarren Fletcher and Craig Bellamy double Micheal Owen with a Fergie time winner. One of the best Manchester derby matches have watched. Entertaining from the start to the final minute.11:20 AM · Aug 5, 20213415Remember Man United 4-3 Man City ?Ben Foster vs Tevez at CityDarren Fletcher and Craig Bellamy double Micheal Owen with a Fergie time winner. One of the best Manchester derby matches have watched. Entertaining from the start to the final minute. https://t.co/XvgvEQSgXbDarren Fletcher made 342 appearances for Manchester United, scoring 24 goals and setting up a further 29. He won five Premier League titles, one FA Cup, one Club World Cup and one Champions League title with United.Fletcher also made 80 appearances for Scotland, scoring five goals. He retired from the sport in 2019, and is currently working as Manchester United's technical director.