So this is why Doc Rivers and his coaching staff were so happy to have two solid days of practice this week.

The Celtics more prepared to take a final exam than the Utah Jazz did to take a pop quiz as the C’s systematically took apart the Jazz, 105-86, at TD Garden.

The Celtics held the Jazz to 37-of-79 shooting for 46.8 percent. But most impressively, they forced Utah, a team that prides itself on execution, to commit 21 turnovers.

Apparently the Celtics were listening when the coaches, starting with defensive guru Tom Thibodeau, preached about staying ready for the pick-and-roll and not letting Utah’s big men of Carlos Boozer and Mehmet Okur get easy baskets underneath.

Afterward, the Celtics were appreciative of their coaches’ preparation, as was head coach Doc Rivers.

Rivers said his team executed from the very beginning, thanks to the preparation.

Rasheed Wallace said it all about preparation by the coaching staff.

Wallace said the Celtics got back to the basics on Wednesday.

Paul Pierce said there was no doubt that the three days helped.

Pierce said the Celtics looked a lot sharper after their practice.