The Dutchman has looked on borrowed time since a dismal December has seen United go eight games without a win in all competition, scoring just once in their last four Premier League games against Bournemouth, Norwich, Stoke and Chelsea.
Smalling, however, expects Van Gaal to stick to his guns despite the mounting pressure from fans and media.
“He has been himself from day one that we met him to how he is now,” he said.
“He is not going to change and that is why he has had a lot of success throughout the years. I can’t ever see him changing because he’s got a track record.
“After the Stoke game it was difficult for much to be said and then on Sunday it was a case of turning our attentions straight to Chelsea. We were quite lucky we had another game straight after and that we could put it right.”
United dominated large spells of the game against Guus Hiddink side but were unable to find a breakthrough and notched their sixth goalless draw at home of the season but Smalling indicated there were plenty of positives to take from the performance.
“The performance was what we’ve been looking for,” he said. “We will take confidence from the game.
“We caused Chelsea a lot of problems, especially when they played with a back four that barely moves and two defensive midfielders. So to create that amount of chances is a positive.
“A lot of players will take a lot of confidence from the fact that we are getting into those positions and causing teams a few troubles.
“People weren’t afraid to get their shots away. On another day we would have taken those chances. It boils down to a bit of luck.”