MIAMI — The facts of postseason life were turned inside-out by the Heat Sunday. One team lacked cohesion and trust, and it wasn’t Miami.

Was it arrogance or uncertainty that undid the Celtics throughout their 99-90 Game 1 loss?

All they knew was that Paul Pierce (19 points and four turnovers) had himself thrown out the game after being outsmarted by Dwyane Wade with seven minutes remaining in the game.

Pierce made two mistakes uncharacteristic of a future Hall-of-Famer who should know better. Just 59 seconds before his ejection.

Wade and Jones (25 efficient points) had dumped the Celtics in a deep 87-74 hole at the time of Pierce’s ensuing run-in with Wade, which makes Pierce’s ejection less the cause and more a symptom of Boston’s opening-game downfall. Wade was running the baseline defensively when he bore through a Pierce screen. Referee Ed Malloy instantly called double technicals on both stars, and then pointed Pierce to the locker room.

“I was trying to get through a screen,’’ said Wade. “I ran through it. He (Pierce) followed me. Paul had some words for me and the referee thought it was a little too much.’’