By Matthew Geagan, CBS Boston

BOSTON (CBS) — Wednesday night was the same old song for the Boston Celtics. Fall behind early because of their extreme lack of effort, make a late run to get close, but come up short and suffer another loss.

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Brad Stevens would love to see his team change the channel and put on a different tune, but right now, he isn’t sure if the they’re capable of doing so. The Boston head coach called out his team’s effort and ability to respond to adversity after Wednesday night’s 113-108 loss to the Mavericks, which dropped the Celtics to 23-25 on the season.

“I’ve been around good teams and I’ve been around bad teams, and we’re very average right now,” Stevens said, putting things lightly.

If only the Celtics were average, they would probably be at or slightly above .500 and not be entrenched in the NBA’s play-in round. But the Celtics can’t seem to do anything consistently, aside from lose games in a frustrating manner.

Star players are salivating to play the Celtics right now. Luka Doncic received little resistance from the Boston defense and hit 11 of his 15 shots (including seven of 11 from three-point land) for 36 points. As a team, the Mavs hits 19 of their 39 three-point attempts.

The Celtics, meanwhile, were a dreadful 11-for-47 from deep. They fell in love with the three once again, relying on long distance shots that weren’t falling despite hitting 60 percent of their two-point attempts.

Boston got behind Dallas by 23 points in the third quarter before slowly whittling that deficit to 17 early in the fourth. The Celtics kept chipping away and eventually got to within two in the final minutes. It was a good job, good effort scenario, but once again, it was too little, too late.

Stevens said this team has the reputation of not being able to respond until it’s too late, which is not a great reputation to have in the NBA.

“The most frustrating part is we let adversity take us out of what we’re doing for too long,” said Stevens. “When adversity hits, we nosedive.”

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That is the story of the 2020-21 Boston Celtics: Too little, too late. Wednesday night was just a remix of recent losses to Milwaukee, Memphis and New Orleans.

“It’s easy to play when you’re down,” Stevens said. “The other team has all the pressure in the world when they’re up 23; you’re just playing free. We have to respond better in the middle of the game and we just haven’t.”

Maybe the Celtics have a run in them to close the season, enough to climb out of the eight-seed and the playoff to get into the playoffs. But they’ve shown nothing to convince us that they’re a team capable of rattling off a bunch of wins in a row.

“It’s not time to dream about the future; it’s time to do it now,” Stevens said. “We need to play better. We need to show up and compete every night with great urgency all the way through the game, regardless of what just happened. So I don’t really care about the future and I don’t really care about the first 48 games. What are we going to do? That’s the question. It’s time to show up.”

The last time Stevens called out his team, the Celtics won four straight ahead of the All-Star break. It made us think that maybe, just maybe, things would get a little better.

But since sending Jayson Tatum and Jaylen Brown to the All-Star game, the Celtics have gone 4-8. They’ve started their seven-game homestand, and welcomed fans back to the Garden, with two straight losses. So here we are again, with the Celtics sitting two games below .500.

But this time around, there are only 24 games left in the season. Time is running out, and the Celtics know it. As Stevens said, they need to show up.

“Even though we had a tough game, we still had an opportunity to win,” said Brown, who pointed to the ongoing continuity issues with the roster. “We are still challenging ourselves to put 48 minutes together. We have 20-plus games left and still have a chance to do so. I just want to encourage everyone and inspire everyone to do that.

“Everyone can be pessimistic and pick everything apart, but that doesn’t help,” Brown added. “We just have to put our best foot forward.”

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“We can’t give up,” said Marcus Smart. “I think that’s really the key. I think we’re gonna turn it around. I don’t know when. But we’re still right there, enough time to get to where we want to go, and hopefully catch a rhythm.”