The summer signing from Monaco, who spent the second half of last season on loan at the club, is still finding his feet after rejoining.
And Maddison believes that as they get more training sessions and games together, Tielemans will find his place in the team's style.
"Youri's a fantastic player," he said to reporters. "Whenever I get asked about Youri I always say how good he is.
"Just watch him for 15 minutes and you'll see. He oozes quality on the ball.
"Maybe Saturday wasn't his best game, but everybody is still getting up to full fitness levels, three games into the season.
"But come the end of the season, I think everybody will be saying what a signing Youri was."