The sides meet in Wednesday's third-round replay at Old Trafford after Robin van Persie rescued a 2-2 draw in the first game with a superb injury-time equaliser.
The Hammers had overturned Tom Cleverley’s first-half opener through two towering James Collins headers, which capped a physical display from the home side.
De Gea told MUTV: “We conceded two goals from headers in the first game and it’s a type of play that you come across in this league quite a bit.
“But we have players at the back who are perfectly capable of dealing with the threat of big powerful strikers who like the ball in the air. We have enough nous to cope with that.
“It’s something we work on and try to come up with solutions in training."
The Spaniard acknowledged the challenge provided by Hammers skipper Kevin Nolan inside his penalty area during the first match. "It’s made even more difficult when you have a tall player like Nolan as well.
“But if there’s a big man next to you it almost gives you more encouragement to come out with more force and strength to take everything and come away with the ball.”
De Gea insists people should make no mistake about the importance of the cup to United.
“Whatever game you’re playing in, it gains importance when you play for this