Real are poised to test United’s resolve to keep De Gea with a £60million bid for their long-term target, whose move to the Bernabeu collapsed two years ago on deadline day.
But ahead of their clash with Real Madrid today, De Gea’s United and Spain team-mate Herrera underlined the importance of keeping the man he believes is currently the best keeper in the world.
“I’m repeating myself every day, but he’s a goalkeeper who can give you points and that’s very important,” said Herrera.
“I want to keep him here, to play with him, because he’s a fantastic keeper and also my friend.
“I think you can see he’s very focused on Manchester United and he’s doing a fantastic job for us.
“It’s like if you were to lose the top three in any position – like David is, like [Paul] Pogba is, like [Romelu] Lukaku is, like Marcus Rashford can be.
“We don’t want to lose them, we want to keep them, and David is in the top three. For me, he’s the best in the world, so I want to keep him here at United.”
United have handed their back-up keeper Sergio Romero a new four-year deal amid the ongoing uncertainty over De Gea’s future, with the Argentina No.1 ready to step up if he does leave.
Herrera also believes United have struck a significant edge in next season’s title race by snatching Lukaku from under the noses of rivals Chelsea in a £75million deal from Everton.
Lukaku produced a stunning strike from an outrageous angle in United’s 2-0 derby win over Manchester City in Houston, although Herrera said the Belgium star brings more than just goals.
“He’s a top, top, top player,” said Herrera. “The way he plays for the team is the thing I like most about him.
“It’s fantastic the way he plays, the way he comes to the midfield to help when the ball is there.
“When opponents have the ball forward, he’s always thinking how to help the team, in terms of defensive work.
“We’re so lucky to have him, and if he scores, then even better. The work he did against City was brilliant.
“Time will tell [if he can be the difference in the title race]. Then we can talk about it. Last season we won three trophies, but we didn’t fight for the nicest one, the Premier League.
“It’s not going to be easy to win three trophies again this coming season, because that’s very difficult.
“We’re happy, we’re working hard, we know the way our manager wants us to play and I think there’s a good understanding between us and the manager, so I’m very optimistic.
“But we have to respect every opponent. City, of course, are going to be fighting for every title, they are spending money for it, and it will be a very good race for the trophies next season.”
With United having already signed Lukaku and Victor Lindelof, and looking to add at least one more player before the season starts, Herrera is confident they can push for the title.
“We won three trophies last season,” said Herrera. “But we want to fight for the Premier League.
“We had a very good season, a successful season, the last game [the Europa League final] was a really important game, which we won, so we can say we had a very good season.
“But now we want to fight for the Premier League. I don’t like to compare the players between last season and this one.
“But we have the same ideas, the same manager and we’re going to work the same way. But the draws we had at home last season, we have to improve that.”