It was the legendary Manchester United manager Sir Alex Ferguson who said the golden words, "Attack wins you matches, defence wins you titles." It would seem Manchester United have always lived by that dictum since they are one of the most decorated football clubs in the world.They have been going through a lean patch in recent times but it wasn't too long ago that the Red Devils were one of the most exciting and ruthless outfits in Europe. The never-say-die spirit is embedded in the club's DNA and they have spawned many footballing superstars over the course of history.They say that some of the players in the current crop lack the warrior-like mentality that Manchester United players of yesteryear used to possess. Some of those footballers looked determined to bleed and torture themselves on the pitch for the team.Manchester United have housed some of the greatest defenders in English football historyA formidable backline is essential for any side that harbors title aspirations and Manchester United are one of the most successful clubs in the history of the game. Suffice to say, the club has been home to some of the best defenders of all time.Without further ado, let's take a look at five of the greatest defenders to have donned the storied red and white kit of Manchester United.#5 Rio FerdinandManchester City v Manchester United - Premier LeagueRio Ferdinand is one of the most decorated English footballers of all time. He is undoubtedly one of the best centre-backs of his generation. After starting out at West Ham United, Ferdinand made the switch to Leeds United in 2000 and became their captain in 2001.He then moved to Leeds' arch-rivals Manchester United in 2002 on a deal worth £30 million. Ferdinand spent a large portion of his academy days as a centre-forward. As a result, when he made the transition to centre-back, he became a defender with excellent technical qualities.He was phenomenal with the ball at his feet and was given the freedom to gallop forward and play progressive passes to his midfielders and forwards. Ferdinand was also formidable in the air and had electric pace in his prime years.He provided the silk to Nemanja Vidic's steel and the duo are still regarded as the greatest centre-back pairing in the history of the Premier League. Ferdinand played 455 games across all competitions for Manchester United.He won six Premier League titles, one Champions League, two League Cups and one FIFA Club World Cup with the Red Devils.UEFA Champions League@ChampionsLeague🗣️ "I wanted it to go down as the best partnership the club had ever had. " Rio Ferdinand & Nemanja Vidić were a formidable duo @rioferdy5 | @ManUtd | #UCL8:40 AM · Mar 26, 2021193444092🗣️ "I wanted it to go down as the best partnership the club had ever had. "🔴 Rio Ferdinand & Nemanja Vidić were a formidable duo 💪 @rioferdy5 | @ManUtd | #UCL https://t.co/TSqE5AXbrf#4 Gary PallisterGary Pallister in action against Wimbledon, in a Premier League match at Selhurst Park, 7th March 1995Gary Pallister is considered to be one of the best centre-backs to have played for Manchester United. He was a strong, athletic presence at the back and alongside Steve Bruce, he formed one of the best centre-back partnerships of all time in English football.Pallister joined Manchester United in 1989 for £2.3 million and went on to make 437 appearances for the Red Devils. Pallister was chosen as the PFA Player of the Year three years later in 1992.The Englishman spent nine years at Manchester United, winning four Premier League titles, three FA Cups, one English League Cup, one UEFA Cup winners' cup and one UEFA Super Cup.Manchester United@ManUtdGary Pallister was the hero 20 years ago today, scoring twice in a 3-1 win at Anfield!2:30 AM · Apr 19, 20171603541Gary Pallister was the hero 20 years ago today, scoring twice in a 3-1 win at Anfield! https://t.co/eOsMwWMq9E