By Matthew Geagan, CBS Boston

BOSTON (CBS) — The Celtics did not play like a desperate team on Wednesday night. They were sluggish to start Game 4 against the Miami Heat, and then continued to play some pretty sloppy basketball throughout.

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Now they’re just one loss away from being sent home from the NBA bubble. Miami took a 3-1 series lead in the Eastern Conference Finals with a 112-109 victory on Wednesday, meaning Boston will be fighting off elimination come Friday evening.

The Celtics better come out with a lot more juice than they did Wednesday night, otherwise their bubble is going to burst pretty quickly. They didn’t have any sense of urgency when Game 4 tipped off, and Miami took control early despite looking pretty rusty themselves following a three-day break in the series.

Boston committed 11 turnovers in the first half and 19 overall in Game 4, leading to 17 points for Miami. Those miscues wiped out the fact that Boston shot the ball better and made more threes than the Heat, who didn’t play particularly well either on Wednesday night. But Miami got a career-game out of 20-year-old rookie Tyler Herro, who poured in 37 points and seemingly made every big basket that the Heat needed to hold off a late charge by the Celtics.

The C’s were at a loss as to why they came out so flat in their biggest game of the season. But they’re well aware that it can’t happen again.

“I cant explain why. I don’t know, to be honest,” said Kemba Walker. “That’s really hard to hit, that we came out flat. We have to be better. That’s it.”

“We have to be aggressive and take care of the basketball,” said Jaylen Brown. “Defensively, when guys get going we have to step up a little more to slow them down. We have to set the tone better from the start. A lot of that is me, so coming out next game that’s what we’ll be looking to do.”

The Celtics were careless with the ball throughout the game and didn’t look at all like a team that was down 2-1 in the series. Jayson Tatum didn’t have his usual burst and started 0-for-6, putting up his first scoreless first half of the season.

“I wasn’t aggressive enough. I didn’t score in the first half and that was unacceptable,” said Tatum, who finished strong with 28 points in the second half. “I have to play better, and that’s what I tried to do.”

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But it wasn’t enough, as the Celtics continued to cough up the ball at key moments. They committed seven turnovers in the fourth quarter.

Now they face a 3-1 deficit in the series. Teams that have gone up 3-1 in the Conference Finals have gone on to win the series 50 times in 54 opportunities.

Impossible for the Celtics? Not at all. Heck, the Denver Nuggets have overcome two 3-1 holes in this bubble version of the NBA playoffs. The Celtics franchise has overcome the vaunted 3-1 series deficit twice in its illustrious history, doing so back in 1968 and 1981.

If this current group of Celtics want to join those two teams, they’re going to have to be better starting Friday night. A whole lot better.

“We have to leave it all on the floor. We just have to win one game at a time,” said Tatum. “We don’t have to win the series next game. We have to give it all we’ve got because it’s win or go home from here on out. That’s the approach we have to take.”

“I believe that we can still come back and win,” said Brown. “We all have to believe in it and we all have to come out and play like it. Starting now, starting next game, we have to want it more. It’s not going to just fall in our laps.”

The Celtics have told us that they’re a contender all season. They’ve said they would fight and find a way to put it all together throughout their struggles in the playoffs. So it really shouldn’t be much of a surprise that they feel they have what it takes to overcome a 3-1 series deficit.

And if they play with a little more urgency from the jump on Friday night, and take much better care of the ball (and Jayson Tatum hits more than zero of his first-half shots), they’ll have a good shot at slowly climbing up that mountain. Hopefully they’ll play with an actual sense of urgency now that their backs are truly against the wall.

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Otherwise, they’ll be leaving Orlando empty-handed.