Ten Hag keeping United players 'on their toes' with team selections, says Shaw
Cristiano Ronaldo (37), United's top scorer last season with 24 goals, and captain Harry Maguire (29) have both been dropped for extended spells in the current campaign.
Ten Hag was making sure players give 100% every day to try to secure a spot in the side, Shaw said.
"The good thing with this manager is that if you're not playing well then you won't play," he told the National in an interview published on Monday.
"In the past, that's not been the case but I think the good thing about this manager is that he's keeping everyone on their toes. He makes sure that everyone is 100% every day. If you're not at it then you won't play. That's a positive thing."
Shaw has also found himself benched this season.
He was dropped after back-to-back defeats by Brighton & Hove Albion and Brentford in August but has worked his way back into the side, starting their last two league games.
"To be honest I didn't really need (Ten Hag) to say anything to me," Shaw said. "I knew the first two games were nowhere near good enough. I completely understood that it was my time to come out of the team.
"The results were bad, my performances were not good enough. I just had to keep training hard every day so the manager could see how hard I was working."
United, who are fifth in the Premier League, host third-placed Tottenham Hotspur on Wednesday.