Van Gaal's first competitive game in charge of United was a 2-1 home defeat to the Welsh club at the start of last season.
Swansea then won the reverse fixture by the same scoreline in February to record their first ever double over United on the way to their highest Premier League finish of eighth place.
United eventually finished fourth but look to have a far more balanced and competitive squad this season.
And van Gaal believes his side is better equipped to face Swansea this weekend than they were last August on the back of a draining pre-season tour of the United States.
"The first match I played was against Swansea. We lost and now I have to play the 50th match," van Gaal said ahead of the trip to the Liberty Stadium.
"I hope we can show how we have improved because that is the main thing. Last year we lose only against Swansea, all the points, and I always want improvement of my team and players.
"I think the first match last year we were not well prepared because of the USA tour and I have explained that already more than 20 times.
"The second game against Swansea it was a very unlucky game for us. We were prepared but I think Swansea has a very good team, this year and last year.
"They proved it. They drew at Chelsea and won against Newcastle so when I see the individual players they have quality.
"It shall be very difficult to beat them but we are better prepared than last year."
Both United and Swansea are unbeaten so far this season.
And Swansea manager Garry Monk wants his players, who have already held champions Chelsea to a point this term, to draw inspiration from last season's efforts against United to spring another surprise.
"It's always very difficult when you face the big clubs," Monk said.
"They (United) have added a lot of quality and depth to their squad and have world-class players.
"We are the underdogs, but we're at home and we want to put on a performance in front of our own fans.
"There is plenty of motivation for the players after our two wins last season and we'll use that going into this game.
"We believe in ourselves, we have our own way of working and that will be no different this weekend.
"We will probably have to produce our best performance of the season so far to come away with the result."
United could have defender Marcos Rojo in their squad for the first time this season after he played for an hour in a mid-week friendly against Ajax.
Van Gaal's side will be without the injured Adnan Januzaj, but they welcome Marouane Fellaini back from a three-match domestic suspension.
England defender Phil Jones is still absent with mild thrombosis, while Swansea have no injury worries.
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