The Netherlands are out for revenge four years after the Americans beat them 2-0 to lift the trophy and two years after the US knocked them out on penalties in the quarter-finals at the Tokyo Olympics.
"This is going to be an incredibly difficult match up, very challenging," said Morgan, who is competing in the tournament for the fourth time.
"We watched the Netherlands the other night, and they have a lot of the same players as we played them in the World Cup four years ago."
The Ninth-ranked Netherlands are without their record goalscorer Vivianne Miedema (27) but are still widely expected to be the biggest hurdle for the four-times champions United States in Group E after they beat Portugal 1-0 on Sunday.
The American defence was solid in their 3-0 opening win over Vietnam on Saturday, scarcely letting the World Cup debutants into the final third.
But the US spurned several chances to find the net and Morgan, who failed to score a first-half penalty against Vietnam, conceded that there is room for improvement.
"We saw a lot of glimpses of our potential, but I feel like we weren't always clicking on the field. I feel like some of the plays that we had were a little forced or rushed," said Morgan.
"We know that we have to be at our best, and we're doing everything we can at the training field, in the meetings, watching video, doing everything we can. But this is going to be a very big match up."