The Spanish playmaker could do absolutely nothing to stop his attempt at blocking an Eric Pieters cross deflecting the ball past David de Gea in the 18th minute of the game at the BET365 Stadium.
Just take a look – how unfortunate is this for Mata?
Mata is usually so reliable going forward and back on the pitch, but there’s literally nothing he can do to stop the ball narrowly missing de Gea to find the back of the net.
It’s far from the start United would have wanted going away against a Stoke team who are usually pretty strong at home.
If Jose Mourinho’s men can recover to win then it could be vital for their title hopes.
They trail league leaders Chelsea by 12 points, but are just four outside the top four and will move just two away from rivals Liverpool after their disappointing 3-2 defeat to Swansea at Anfield earlier.