United's 3-1 win over Liverpool brought to an end their pre-season trip to the United States, with Steven Gerrard’s first-half penalty giving Brendan Rodgers' side the lead only for Wayne Rooney, Juan Mata and Jesse Lingard to respond after the break.
But new United manager Van Gaal was not getting carried away, following their unbeaten five-match tour, saying: "Today was not so good.
"Against Madrid it was fantastic when we dominated the game against the Champions League winners – then I was very pleased.
"Today we have struggled, it was too much playing two in two days and all the travelling. But we have pleased our fans."
Van Gaal said before the game he will make his decision on who to keep at Old Trafford – and who can leave – when they return home to Manchester.
As for giving clues, the Dutchman was remaining tight-lipped: "I won't tell them through the media. I’ll speak to the players and will say it honestly. I won’t come with the axe – it’s not like that."
With regards to United's trip across the Atlantic, Rooney added: "We've worked hard in training to adapt to the way the manager wants us to play and had some good results.
"He came in, looked at the players he had, and chose a system that suited the team."
As for the final of the International Champions Cup, he added: "Today in the first half Liverpool were the better team. We were poor and didn't move the ball quick enough.
"We knew we had to put that right. The second half we came out and played very well and deserved the win."