van Gaal was pleased with Anthony Martial's decision to rule himself out of the game during the warm up.
The French forward pulled out after feeling his hamstring less than 20 minutes before kickoff, but the United boss was happy that the 20-year-old had taken precautions, as he didn't want him to exacerbate the problem - especially given the club's injury woes.
"The first impression is that it is not heavy," said Van Gaal on the injury after the game.
"What is remarkable is that he stepped down himself and I like that very much.
"I think he is smart and wise to step out, because it was not a rupture, it was a tight hamstring.”
Van Gaal's words come just two weeks after the Dutchman appeared to criticise club captain Wayne Rooney for playing while injured against Sunderland.
Rooney, 30, picked up a knee ligament injury in the 2-1 loss at the Stadium of Light and now faces at least another month on the sidelines.