Chicharito has hailed the improvement of the Spain U21 star.
Mexico international Hernandez told Inside United: "For me he's the best goalkeeper in the world.
"We all talk about development and having to go down a certain career path and, of course, at his age many people would have been scared to give him the place he's earned for himself.
"But I think that this season (2012-13) he's really benefited from being given the opportunity to play on a regular basis.
"He was first choice between the sticks and I think that any player in the world shows his true ability when he gets the chance to have a decent run of games in the side, and David has really shown his quality.
"He was voted the best keeper in the Premier League, so I'd say he's doing very nicely thank you."