Timothy Fosu-Mensah believes Manchester United goalkeeper David De Gea is possibly the best goalkeeper in the world after the Spaniard's standout performance in United's 2-1 defeat of West Ham in their FA Cup quarterfinal replay on Wednesday.

The Spanish international made a number of fine saves to help Louis van Gaal's club advance into the next round, impressing the 18-year-old Fosu-Mensah along the way.

Speaking to the club's official website on Thursday, the Netherlands youth team defender hailed his teammate as one of the best at his position.

"David is one of the best goalkeepers in the world, maybe the best," Fosu-Mensah said.

"It's very good to have a goalkeeper like that in your team. He can save you points or save you in the cup.

"I think players like Michael Carrick, Daley Blind and Chris Smalling kept the team together in order to win this match. It was very important because they give confidence to everyone on the pitch.

David De Gea helped Manchester United into the FA Cup semifinals. AP Photo/Alastair Grant

"I saw [Cheikhou] Kouyate score and thought 'no, no' but then I saw the linesman's flag so I was relieved it was offside.

"It was a very big game and a great win. I'm happy we won this game and that we can go to Wembley for the semifinals. It's very special because it was a huge occasion."

The match represented just the third United start for the young Dutchman, who hailed the opportunity as a valuable growing experience.

Fosu-Mensah said: "I have not really faced an atmosphere like that but I'm getting used to it more and more. It's great for my development to obtain such experience.

"I went from right-back to left-back and I do my best in every position and just do what I can for the team."