The big day has arrived.

Joe Mazzulla will lace up his shoes for a regular season game as an NBA head coach for the first time Tuesday.

“You definitely have moments of gratitude. You definitely have moments of, like, it’s special to be here,” Mazzulla told reporters Monday. “You have to take those moments in.”

Just three years ago, Mazzulla was a head coach at Division II Fairmont State, located roughly 20 miles south of the WVU Coliseum, where he played collegiately.

Mazzulla, thrust into the interim head coach role in September, will make his NBA regular season head coaching debut against the Philadelphia 76ers, in what some believe could be an early preview of the Eastern Conference Finals.

“I think you got to focus on the most important things,” said Mazzulla “As soon as the game starts, it’s how can we execute.”

In charge of the team for less than a full month, Mazzulla is settling into his role. He is still working to build relationships with the players he’ll be leading into the 82-game NBA regular season, though he is familiar with many of them after being an assistant for the last two seasons.

Mazzulla won his head coaching debut at the start of the preseason. Tuesday night will be different.

The game counts, and some of the national spotlight will be on Mazzulla, who is doing his best to keep that spotlight on his players on the court.

“You’ll have some small moments here and there,” said Mazzulla, “but I think it’s more about what we’re trying to accomplish as a team, and just making it about our guys, and how good they are and where they can go.”

Boston’s season opener against the Philadelphia 76ers will be televised on TNT. Tip-off is scheduled for 7:30 p.m. ET.

Four of Mazzulla’s first eight games as head coach will be nationally televised. Mazzulla and Boston will face Miami (Oct. 21), Cleveland (Nov. 2), and Chicago (Nov. 4) on ESPN, with all three games scheduled to start at 7:30 p.m. ET.