Van Gaal focused on Swansea opener
United capped an unbeaten tour of the United States with a come-from-behind 3-1 victory over Liverpool in the International Champions Cup final at Sun Life Stadium in Miami.
Wayne Rooney, Juan Mata and substitute Jesse Lingard were all on target in the second half as United cancelled out Steven Gerrard's 14th-minute penalty to lift the trophy.
While victory ensured United returned to England on the back of five consecutive pre-season wins, Van Gaal played down its significance as the Dutchman prepares for the club's first league fixture against Swansea City at Old Trafford on August 16.
"It's nice for the fans in the USA and also at home that we beat Liverpool," he said at his post-match press conference.
"I think we gave a lot of pleasure to the fans and that's very important.
"Of course, it's better to win than to lose in pre-season but the most important game is against Swansea City. That's the one we have to win."
Rooney was handed the captain's armband for the first time in the USA and he staked his claim with a well-taken goal in the 55th minute, side-footing the ball into the far corner for his fifth goal on tour.
The England international's performance saw him named player of the tournament, leading to praise from Van Gaal, who also lauded the team's defence.
"He's always a winner," van Gaal said. "I think he deserved to win the award because he made a lot of assists and scored goals.
"But we also defended well - there are a lot of defenders who could also have been the most valuable player of this tournament.
"For Rooney, the goal was very important. It was a wonderful goal. You see the attack and what he did to push the ball under the legs of the goalkeeper and also in the corner. It was also a great cross from [Javier Hernandez] Chicharito."
United wrap up preparations for the Premier League season with a friendly against Spanish side Valencia on August 12.