Manchester United legend Gary Neville is stunned by David de Gea's form slide has stunned him.

De Gea let slip two goals in defeat to Manchester City.

"The goalkeeper has to do better," Sky Sports pundit Neville said following the game. "David de Gea, he's been magnificent for man united for so many years but this season it's just not happening for him.

"Those feet are letting him down. So many times we've seen them kick the ball away. Straight at him, off his shin, into the back of the net.

"I was in the Nou Camp for that mistake for the Messi goal and it was something that shook me, watching David de Gea make a mistake like that.

"This one was not as bad but still for him, a really bad error. It's not happening for him at the moment, he's going through a really bad time, a difficult time."