Shaw claims no-one should be fooled by Solskjaer's nice-guy image and says the United caretaker boss has a tough streak in him.
The England defender says Solskjaer will not tolerate anyone letting their standards slip.
“It's just amazing to look at the job Ole has done since he came in," he said. “How much he has turned it around and how much the place is in a positive way now.
“He knows how good we can be and, if we're not up to his standards or the standards of Manchester United, he will certainly let you know.
“We've had a few moments like that where we might have been comfortable in a game, but got a bit sloppy.
“He's the manager and he tells the players what he wants. It's good and what we need sometimes, a kick up the backside from the manager, if we're getting too comfortable.
“It keeps everyone on their toes, but he's an amazing guy and a brilliant manager."