Game 4 isn’t a must-win for the Knicks, but it’s as close as it can be to being one.

On Saturday, the Heat secured a 19-point win in Miami and a 2-1 lead in their Eastern Conference semifinal series.

For the Knicks to even things up and avoid being pushed to the brink of elimination, they’ll have to do better than the season-low 86 points they put up in the loss.

“The bottom line,” coach Tom Thibodeau said on Sunday, “is we all have to play a lot better.”

That may not include Immanuel Quickly, the third-year guard who has emerged as one of the team’s top bench options, as he deals with a sprained left ankle and is listed as “doubtful.”