3. Nemanja Vidic and Rio Ferdinand
Nemanja Vidic has often been regarded as one of the greatest defenders of all time, so a defensive partnership with Rio Ferdinand was always going to prove to be a successful one.
And didn't it just.
During their time as a pairing, Manchester United have won four Premier League titles, and a Champions League - as well as two league cups.
The pair also helped United make a new Premier League record of 11 consecutive clean-sheets, in front of goalkeeper Edwin Van Der Sar.
Perhaps now they are not as strong as they once were, but they will always be remembered for playing in a period that was arguably United's finest in their history.