Forward Jayson Tatum drives to the basket in the second half of an the Celtics’ 124-97 win over Chicago in an NBA In-Season Tournament game Tuesday in Chicago. Steven Senne/Associated Press

BOSTON — Jaylen Brown scored 30 points, Jayson Tatum had 21 and the Boston Celtics routed the Chicago Bulls 124-97 on Tuesday night to advance to the quarterfinals of the NBA In-Season Tournament.

The Celtics won a three-team tiebreaker with Orlando and Brooklyn via point differential to take Group C and earn the No. 3 seed in the Eastern Conference. They will visit the No. 2 Indiana Pacers next week.

The Celtics made a season-high 21 3-pointers, getting four each from Al Horford and Jrue Holiday. All five Boston starters scored in double figures.

Horford finished with 16 points and nine rebounds. Holiday, who returned after missing two games with a sprained right ankle, had 14 points, nine assists and seven rebounds.

The Celtics extended the Bulls’ losing streak to five straight. They outrebounded the Bulls 51-38 and shot 52% (47 of 90) from the field.

Although the Celtics began the day with the best record in the NBA, Boston needed a win and a huge scoring night to have a chance at reaching next week’s quarterfinals.

DeMar DeRozan and Coby White led Chicago with 19 points apiece. Patrick Williams added 14 points and seven rebounds for the Bulls, who could not stop the Celtics’ outside shooting.

Boston finished 21 for 49 from beyond the arc. It topped its previous high of 20 3-pointers set Nov. 1 against Indiana.

Ayo Dosunmu added 10 points for the Bulls, who have lost eight of nine.

Boston scored 38 points in the second quarter on its way to a 69-50 halftime lead. It continued to roll in the third. Tatum made a layup and a 3-pointer to help the Celtics increase their advantage to 78-55.

After committing just three turnovers in the first half, Chicago had three in the third as the Celtics capitalized on every Bulls mistake and stretched the lead to as much as 32.

With the point differential in mind, Boston continued to push. Tatum missed a long jumper, but Sam Hauser was there to slam back the rebound for a 104-75 lead with 8:52 left in the game.