© PA Photos
Visiting United began the match in the ascendancy and went on to break the deadlock in the fourth minute. Wayne Rooney got free down the right and cut the ball back for Robin van Persie, whose shot struck the post. The ball rebounded against David Luiz and dropped into his own net.
Their lead was then doubled in the 12th minute when Van Persie side-footed in a low cross from Antonio Valencia.
The remainder of the half was dominated by the hosting Blues, who saw a number of shots saved by visiting goalkeeper David de Gea.
Mata had another chance in stoppage time, but De Gea managed to keep him out with his legs.