Kastelic made it 3-2 at 10:22 of the third period with a shot from low in the left circle to the upper right corner during a delayed penalty.
He also had an assist, Sean Kuraly had a goal and two assists against his former team, and Henri Jokiharju had a goal and an assist for the Bruins (44-27-10), who were 0-3-2 in their previous five games. James Hagens, the No. 7 pick in the 2025 NHL Draft, had an assist in his NHL debut.
Boston has clinched a berth in the Stanley Cup Playoffs and is two points ahead of the Ottawa Senators for the first wild card in the Eastern Conference with one game left. The Senators have a game in hand.
Mason Marchment and Adam Fantilli scored, and Jet Greaves made 19 saves for the Blue Jackets (40-29-12), who are 3-8-1 in the past 11 games.
The Blue Jackets trail the Philadelphia Flyers by two points for third place in the Metropolitan Division with one game remaining, one fewer than the Flyers but Columbus holds the tiebreaker. The Washington Capitals are one point behind the Flyers and finish the regular season at Columbus on Tuesday.
Marchment made it 1-0 at 3:59 of the first period. He was parked to the right of the net to redirect a shot from the left point by Dante Fabbro.
Kuraly scored at 10:31 to make it 1-1 off a double tip. Jokiharju’s shot was touched first by Kastelic before Kuraly’s deflection.
The shots at that point favored the Blue Jackets 10-1.
Jokiharju made it 2-1 at 19:41 of the second period from the right dot after Kuraly won a puck battle below the goal line. Hagens, a 19-year-old forward, had the secondary assist.
Fantilli tied it 2-2 at 1:27 of the third period with a breakaway snap shot after a long pass by Danton Heinen.
