Cardiff City ensured both Manchester clubs left Wales without all three points, as a last-gasp equaliser from Kim Bo-Kyung rescued a well-deserved draw for the home side.
Manchester United took the lead in the 15th minute, Wayne Rooney slotting home via a deflection after a misplaced pass led to confusion in Cardiff's back-line.
Questions were asked as to whether Rooney should have even been on the pitch at that point, after he had only been booked for kicking out at Jordan Mutch.
But things got better for the hosts when former United striker Frazier Campbell leveled after an excellent through-ball from Mutch.
Patrice Evra headed in on the stroke of half-time, to give United a lead they barely deserved. But the champions dug in in the second-half, and it looked like they would take all three points.
That was until Kim took a note out of Evra's book and snuck in to head home from a corner, sending the Cardiff City Stadium into raptures.
There was still time for Rooney to completely fluff what should have been an easy goal, attempting to pass to Danny Welbeck when a composed finish was all that was required.
But as it was, the game finished level, leaving United sixth and Cardiff 15th in the league.