David Moyes' side will enter uncharted territory of four successive defeats if they lose to the Swans at Old Trafford for the second time in a week.
United have not lost four matches on the trot in the Premier League era and the last time it happened was in 1981 during Dave Sexton's spell in charge.
But they will claim that unwanted record if Swansea follow up their FA Cup victory which sandwiched the Red Devils' Premier League home loss to Tottenham and the Capital One Cup semi-final first-leg defeat at Sunderland.
Rooney will miss the match as he continues his recovery from a groin injury but he has urged supporters not to desert the club or Moyes in their hour of need.
"The fans' support is very important," the England international told MUTV.
"The fans have been great here, especially now when we are not in the best of form and we have lost the last few games.
"We need them to support us through this time. We will get stronger and we will get better.
"The fans are vital in being patient with us and letting us try to get there. I am sure we will do."
Watch Manchester United v Swansea live from 5.00pm this Saturday on Sky Sports 1HD and Sky Sports 3D