Jose Mourinho believes Manchester United must retain players of David de Gea's calibre to preserve their identity as one of the world's leading clubs.

Spain goalkeeper De Gea was going to be out of contract at the end of the season, but United are announced that they have triggered their option for a one-year extension.

The 28-year-old, who was close to joining Real Madrid in 2015, continues to be the subject of transfer speculation, with Paris Saint-Germain and Juventus credited with an interest.

Mourinho is adamant De Gea wants to stay at Old Trafford and believes it is a mere formality for United, who sit seventh in the Premier League, to tie down one of their most prized assets.

"He wants to stay, of course. I want him to stay, he's the level of player Manchester United needs," Mourinho said.

"If we want to be Manchester United, we need the best players in the world.

"We have the best goalkeeper in the world. The manager wants him to stay, the board wants him to stay, and David wants to stay.

"His agent wants what the player wants. His agent is not manipulative like others. His agent lets him think and decide by himself.

"I think the point is just to agree what the club wants to give and what the player wants to accept. This is just my feeling, they are going to finish well."

De Gea demonstrated his value with a superb stop from a deflected Ulisses Garcia shot in the late 1-0 win over Young Boys in the Champions League on Tuesday.

Mourinho, however, claimed even he could have a kept a clean sheet in that match, such was the limited threat the Swiss side posed.

"[Whether it was] David there or myself it would be the same," the Red Devils boss said.

"Don't say it was an amazing performance. It was a zero performance with one world-class save. He didn't touch the ball and [in the goalless draw with] Crystal Palace he didn't touch the ball.

"But when he needs to touch the ball he's the best."