Guzan expects Villa striker Christian Benteke to test the Spaniard.
Guzan said: "Christian's height is just one of his many strengths. He also has incredible skill.
"But whatever way the ball goes in the net will do for us.
"For De Gea, it is about how he responds to his physical challenge.
"Christian is a handful because of his phenomenal ability in the air. He is strong, a force to be reckoned with."