De Gea garnered plenty of praise after his heroics in the Bernabeu helped the Reds gain the upper hand in the Champions League last 16 tie against Real Madrid.
But the 22-year-old stopper has also been criticised in some sections of the media this season for a perceived susceptibility to crosses and lack of dominance in his area.
That’s an accusation that doesn’t sit well with Chicharito, who told MUTV: “He’s been brilliant. He’s a complete goalkeeper and you can see the great saves he’s made.
“A lot of people who really know about football say he is a top-class keeper. It’s why United bought him.
“People say clearing corners and free-kicks are a weak part of his game but he’s doing brilliantly. For me, in a couple of years or less, he will be the number one in the world.”
Hernandez believes De Gea will continue to flourish at Old Trafford because he doesn’t pay attention to his critics.
“That’s the way he is. He’s very focused and doesn’t listen to all that rubbish they speak about him.
“He has a lot of confidence from us and we tell him every day he’s a very good keeper. He plays and enjoys it. He knows he can be the best in the world and for this club.”