Boston Celtics’ Kyrie Irving, right, grabs a loose ball against Los Angeles Lakers’ Moritz Wagner during the second half of an NBA basketball game, Saturday, March 9, 2019, in Los Angeles. The Celtics won 120-107. (AP Photo/Jae C. Hong)

LOS ANGELES — When the Boston Celtics embarked on a west coast swing to open last week, they appeared to be flirting with crisis. After five losses in six games, coach Brad Stevens was preaching the virtues of “fun,” Kyrie Irving was feeling “overwhelmed” by outside noise, and the collective on-court product was often disjointed and listless.

The ensuing four-game jaunt through the Pacific Division put to bed most of the growing fears: The Celtics were glorious in a blowout of the Golden State Warriors, steady in a last-second win over the Sacramento Kings, and formidable while dissecting the overmatched Los Angeles Lakers.

That third straight win prompted Irving to offer a message to former teammate LeBron James that, while intended as conciliatory, came off a touch patronizing.

“When you’re not eligible to quality for the playoffs, it’s hard,” Irving said. “I can only imagine.”

The long-awaited upswing also prompted the all-star point guard to promise that his team will be “tough to beat” in the playoffs because it possesses enough depth “to make a very deep run.”

Instead of closing their trip on an emphatic note, though, the Celtics succumbed to self-satisfaction and were routed by the Los Angeles Clippers. The no-show in a 140-115 loss on Monday night was a reminder that, for all its talent and experience, Boston resides in the East’s fifth seed because it has shown little interest in displaying night-to-night intensity.

Boston carries itself with a flippancy that functions as both a gift and a curse. Against the Warriors, the Celtics came out loose, racing to an 11-0 lead over the champs and never looking back. Against the Clippers, Irving and guard Jaylen Brown spent a portion of pregame warm-ups doubled over with laughter during a dance-off. The Celtics then proceeded to give up 140 points — the highest point total by a Boston opponent in 25 years.

For some teams, such a loss would have had a sobering effect. Not these Celtics.

“We need to get out of L.A.,” Irving said with a smirk. “I love being out here. But, yeah, we need to get out of here.”

The Celtics embody an archetype that is maddening to high school teachers everywhere: precocious, unfocused and cocky enough to cut classes and skip homework assignments without a healthy fear of the consequences. After all, they tell themselves, they can always pull an all-nighter and ace the final.

Of course, Stevens has made his NBA reputation molding teams with a much different identity: diligent overachievers who left nothing to chance. Perhaps that’s why he sounded a bit envious of Doc Rivers, whose Clippers are closing in on an unexpected playoff berth thanks to sheer energy and discipline.

“They play as hard as anybody we’ve played against,” Stevens said, after Lou Williams poured in a game-high 34 points to lead seven Clippers in double figures. “It’s hard to find a group that plays that well together and that plays with that kind of intensity. I’m sure (Rivers) is having a blast.”

Just as Boston was all too willing to settle for a 3-1 trip, it seems doomed to play out the last month of the season in Jekyll and Hyde mode.

After the win over Sacramento, Stevens spent a practice drilling his team on late-quarter scenarios. The Celtics responded by executing well against the Lakers, but Stevens looked frustrated when Irving carelessly tossed away a possession late in the first quarter against the Clippers.

Similarly, Boston’s perimeter defense looked stout on Saturday, as it held the injury-ravaged Lakers to 5-for-27 shooting from beyond the arc. Two nights later, the Celtics looked unorganized, late and occasionally invisible. The Clippers hit 13 of their 28 three-point attempts under little duress.

And against Golden State, Gordon Hayward poured in 30 points and posted a plus-32 in arguably his best and most complete game of the season. He fared much worse against the Clippers, managing just eight points and a minus-20 in 22 forgettable minutes off the bench.

To a man, the Celtics are well aware of their chronic inconsistency. Boston has its faults, but denial isn’t one of them.

“It’s not like we solved a big puzzle after three games,” Stevens said. “We’ve been all over the map, depending on the week.”

NBA teams draw their identities from their best players, and the Celtics are no exception. While Irving made his name with his wizard-like handles and a Finals-clinching jumper, he built his brand by leaning into his unpredictability.

His musings about a flat Earth, his embrace of Uncle Drew fame while purporting to be sick of attention, and his willingness to lash out one week and then publicly apologize the next can all be viewed as evidence of an innate desire to shift observers off-balance. Whether this keep-them-guessing strategy proves to be as effective in leading a basketball team as it has been for selling sneakers and soda remains to be seen.

Yet the one bankable emotion from Irving — win or lose, happy or sad — is utter self-confidence, derived in part from his careful study of Kobe Bryant’s Black Mamba mantra.

“I’ve been through too many battles,” he said after the Clippers loss. “I don’t have time to keep holding onto emotions from game to game. I’ve been through too much. It’s one game. We know what we have to do.”

With the postseason approaching, the Celtics’ predicament is simple: “We know what we have to do” works equally well as a rallying cry and an epitaph.