By Matthew Geagan, CBS Boston

BOSTON (CBS) — The Celtics offense has been alive and well during the team’s west coast trip. That’s the good news.

The bad news is that their defense was apparently left on the tarmac. The Celtics have allowed an average of 124 points in the first three games of their trip, with the Lakers dropping 117 points on them in Tuesday night’s loss.

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To put it bluntly, the Celtics defense has been an absolute mess the last three games. After holding three straight opponents under 100 points before the trip, Boston allowed the Jazz to drop 137 in the first game out west. The Blazers and the Lakers both scored 117, with the C’s splitting those two contests.

On Tuesday, the game plan was for Boston to force the Lakers to shoot from the outside. Instead, they let L.A. destroy them in the paint, giving up 66 points down low. LeBron James led the charge with 30 points, and only 12 of those came from outside of the restricted area. Russell Westbrook and Anthony Davis added another 34 points from the paint on the way to a 117-102 blowout win.

For a team that prides itself on their defense, the last three games have been a big gut check for the Celtics. Boston head coach Ime Udoka, who is not afraid to call out his team when they lack effort, called out his team for lacking effort on Tuesday night.

“That part was disappointing, as far as them really wanting to put their head down and get to the basket, get whatever they wanted,” Udoka said following the loss. “So we said obviously we’re better than that defensively. We’ve shown that. The effort and lack of toughness showed a little bit tonight.

“It hasn’t happened in a long time,” he added. “So I told the guys it’s a blip on the radar, but we need to get back to it tomorrow and we got a chance to.”

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Not having Jaylen Brown for the last three games certainly doesn’t help Boston’s defensive cause, but the results should still be better than giving up 120 a night. Celtics players were pretty critical of themselves as well, so we should see a much better focus on that end of the floor Wednesday night when Boston concludes its Los Angeles back-to-back against the Clippers.

“Messing up coverages, repeatedly,” big man Robert Williams said of the team’s issues against the Lakers. “It’s completely on us.”

The Celtics trailed by just five at halftime, but the Lakers went on an 11-2 run midway through the third quarter to pull away. Westbrook scored seven of those points to help L.A. build a six-point lead into a 15-point advantage.

“We just weren’t ready for the punch in the second half,” said Williams. “We have to clean it up.”

“I think this may be the second time all season that we didn’t necessarily play harder than the other team,” said Jayson Tatum, who led all scorers with 34 points. “I think it was kind of an ugly game on our part on both ends. We just didn’t have that same pop, and that’s the toughest part about it.”

A win on Tuesday would have catapulted the Celtics out of the play-in section of the standings, so it was a missed opportunity for them to improve their positioning. It also adds a lot more pressure for them to win Wednesday against the Clippers and Friday night when the trip wraps up against the 20-4 Suns. The chances of a winning trip pretty much went out the window with Tuesday night’s loss.

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But more frustrating than the losses are how the Celtics are dropping these games. Maybe their lost defense will show up for the end of the trip, but for a team that is stuck in the bottom of the Eastern Conference playoff picture, the Celtics really can’t afford to have these kinds of stretches.