Growth, at times, can be as painful and agonizing as it is rewarding, and the Celtics experienced that firsthand in their NBA Cup duel with the Magic on Friday night.

During his time suiting up for the Celtics, Lee wore only jersey No. 42 and put up 7.1 points, 4.3 rebounds, and 1.8 assists per game.

The Celtics have prioritized building an unbreakable mindset early this season. Here are nine lessons from their first nine games.

Anfernee Simons played just two minutes in the first half, but he made his presence known in the fourth quarter of the Celtics' loss to the Magic.

Today in Boston Celtics history, Thomas Ernest "Satch" Sanders was born in New York City, New York. Satch -- as he was often called for a nickname -- played his NCAA basketball at New York University, and was drafted by the Celtics with the eighth overall in the 1960 NBA Draft.

Derrick White recalled how head coach Joe Mazzulla played the sound of a machine gun firing throughout a 10-minute zig-zag drill between him and Payton Pritchard.

Pritchard has also set up his teammates to the tune of a career-high 5.1 assists per game. Considering the Celtics depth, there are some lineups that put a lot of attention on Pritchard as the ball-handler and initiator of the offense. That also puts more pressure on him to get his teammates going depending on who’s out there with him.