United come into the game fourth in the table, having won three consecutive league games.
Stoke, meanwhile, have suffered back-to-back defeats to Burnley and Liverpool, and have lost all six of their previous Premier League visits to Old Trafford.
Nevertheless, Van Gaal has warned against complacency as his men look to consolidate their top-four position.
"Winning, for a top club like Manchester United, is the most important thing in a week, or in a day," he said.
"Especially when we are in fourth position in the league table you have to win, otherwise others shall overcome you. Of course I had hoped that we would win on Saturday [against Hull City] but we have to win also against Stoke City.
"But in the Premier League nothing is easy. When you see Liverpool struggling against Stoke City - [scoring in the] 85th minute - that shows.
"You see Arsenal struggling against West Bromwich Albion - they could also have lost.
"Every game is difficult. That is why the Premier League is exciting, because you never know. There is an atmosphere in the stadiums [that is] fantastic and the fans are always supporting their club until the end.
"That is fantastic. That is why I want to work in the Premier League, because of that, the atmosphere."
Van Gaal stated that he would continue to ease Radamel Falcao back into first-team action, as the Colombia international looks to make a full recovery from a calf problem.
"He was not fit to play 90 minutes [against Hull], but for 20 minutes okay," he said.
"I can use him because now he has trained for a full week with the first team. He needs match rhythm."
