United are seeking a fourth successive Barclays Premier League win as they host the Potters on Tuesday night.
United have been inconsistent since Van Gaal took charge in the summer but the Dutchman reflected on their most satisfactory performance to date after Saturday's one-sided 3-0 win over Hull.
The result ensured they maintained fourth place in the table and Van Gaal now wants to make sure they kick on.
The 63-year-old said: "Winning, for a top club like Manchester United, is the most important thing in a week, or in a day.
"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 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."
United will be without forward Angel di Maria after the Argentinian pulled up with a hamstring injury early in the clash against Hull.
The club are still to learn the full extent of that problem but captain Wayne Rooney is expected to be fit after banging his knee on an advertising hoarding late in the game.
Striker Radamel Falcao might also be pushing for a start after coming off the bench to play the latter stages on Saturday following his recovery from a calf injury.
Van Gaal said: "He was not fit to play 90 minutes, but for 20 minutes okay
I can use him because now he has trained for a full week with the first team
He needs match rhythm."
Stoke manager Mark Hughes believes the club can cope with the injuries that are beginning to pile up.
Midfielders Steve Sidwell and Glenn Whelan are the latest to join the casualty list that also includes Victor Moses (thigh), Robert Huth (calf), Peter Odemwingie (knee) and Dionatan Teixeira (broken foot).
Influential centre-back Huth, who has not played a league game for a year after suffering setbacks while recovering from a long-term knee injury, is at least closing in on a comeback.
The virus that swept through the training ground last week also appears to have been cleared, with Phil Bardsley back in the squad for Tuesday's clash at Manchester United after missing Saturday's 1-0 defeat at Liverpool because of the bug.
It was at Anfield, though, where Sidwell and Whelan suffered their injuries, with the latter out for up to six weeks with a grade two tear of a medial knee ligament, whilst replacement Whelan picked up a calf muscle problem and is out of the trip to Old Trafford, and almost certainly Saturday's visit of Arsenal.
Hughes said: "Steve has had a scan and it's slightly better news because we thought he would be out for six to eight weeks.
"But it's not as severe a tear and he is now likely to be out for four to six weeks.
"It's a blow to us with the amount of games we have coming up, but at least we're encouraged by the better news.
"Glenn, meanwhile, has been checked over and it's not a pull, which is also good news, but he's not available for tomorrow.
"These injuries of late have coincided with the illness that broke out last week, which we could have done without.
"We cleared people out of the training ground which enabled us to keep it away from the majority of the senior squad.
"A few went down with it, but if we hadn't have done what we did then we might have been more greatly affected than we were in the end.
"Hopefully now we're over this one.
"As for the injuries, you can't really avoid them because they're occurring in matches and they're difficult to legislate for, even though you try to do everything correctly.
"There's not a great deal we can do about it
It's just a phase we are going through and we're trying to make the best of it."
After back-to-back defeats, Hughes could not have asked for a more difficult task with which to resurrect his side's fortunes than going up against his old club who have won their last three matches
"We've had the two losses, but in terms of performances I've been pleased enough," said Hughes.
"They seem to have run into a little bit of form unfortunately from our point of view.
"If we'd faced them earlier then maybe it would have been easier, but they've had three wins on the trot and they seem to be getting to grips with what the manager wants and how he wants them to play.
"We'll have to play very well, we have to accept that.
"But in terms of confidence going into a game at Old Trafford we're not affected because we've proven this year we can give a good account of ourselves no matter who we play."
Source : PA
Source: PA