The Boston Celtics kept their NBA Cup chances alive with a thrilling win over the Chicago Bulls on Friday, but they still need help to clinch a quarterfinal berth.

Although Boston improved to 3-1 in group play with a +23 point differential, the Atlanta Hawks officially won East Group C with the head-to-head tiebreaker. That means it’ll all come down to Tuesday night for the C’s.

The point differential tiebreaker will decide the Celtics’ fate. To advance to the knockout stage, the C’s need the Orlando Magic to defeat the New York Knicks in their NBA Cup showdown at Madison Square Garden. They also need the Milwaukee Bucks to beat the Detroit Pistons by at least six points OR Detroit to defeat Milwaukee by at least seven points.

The Magic currently lead the Eastern Conference with a +60 point differential in NBA Cup play. The Bucks are +29, the Pistons are +28, and the Knicks are +15.

Before the NBA Cup drama unfolds, the Celtics will take a seven-game win streak into a marquee Sunday matchup vs. the East-leading Cleveland Cavaliers. Boston (16-3) can overtake Cleveland (17-3) for the top spot in the standings with a victory.

Tip-off for Sunday’s game is set for 6 p.m. ET on NBC Sports Boston.