Watch: Xavier Tillman hits huge game-winner for Celtics against Kings

Sacramento looked like it had the game in hand when Keegan Murray blocked Sam Hauser's shot with a one-point lead late. But Hauser knocked the ball away from Murray, and Tillman exploited the defensive chaos for a score.

While the Celtics have a 14-game lead on their closest Eastern Conference competitor, the Western Conference is much tighter. The Kings fell to 44-33, only three games off last year's pace. Last year, they were in third place, while this year, they sit in eighth.

Now, the Kings have the same record as the Los Angeles Lakers with five games to play. That's a huge difference between playing a 7-8 game, with two chances to advance to the playoffs, to facing two single-elimination games just to get the eight seed.

In a game when the Celtics played without Derrick White and Jaylen Brown, the Kings may have thought they won it when De'Aaron Fox banked in a go-ahead three. But Tillman's heroics kept them from a win — and might doom them to a very short postseason appearance.