– Sir Alex.
Sub-plots: United have not lifted the FA Cup since 2004 and Sir Alex's men are desperate to end that drought this season. Surprisingly, only four current Reds - Paul Scholes, Ryan Giggs, Darren Fletcher and Robin van Persie - have lifted the famous trophy, and the latter did so with Arsenal.
Whistle blower: Andre Marriner, a Midlands-based official who has dished out 74 yellow cards in 25 fixtures this season, will take charge of Monday night’s match at Old Trafford. United fans last saw the 42-year-old during a 4-0 win over Wigan on New Years’ Day.
Rivals watch: On Saturday, Arsenal host Blackburn Rovers at the Emirates Stadium before old foes Leeds United host Manchester City at Elland Road on Sunday.