The 26-year-old, who was in excellent form throughout last season, has credited the Dutch manager for improving his game and allowing him to take charge of a Red Devils defence that conceded just 35 goals in 38 Premier League game last season.
"It was great working with Louis and getting a good run of games," said Smalling.
"Knowing Louis, he's one that's very tactically aware. Despite the ups and downs of the season, I think on the whole we as a team were very solid.
"We didn't concede too many goals throughout the season. That's something he really implemented on us, whereas in a couple of the previous seasons we did concede a lot.
"That season he really drilled us from the front right to the back in terms of how we move, how we shift, and that's obviously helped me because that's a large part of my game. I think a lot of the defence took a lot of credit from that."