LOS ANGELES — Al Horford couldn’t help but laugh as a reporter badgered him with questions about what really happened on the Boston Celtics’ cross-country flight Sunday night that has seemingly changed the tenor of the team.

“It was a normal plane ride, it was just long,” pleaded Horford.

And he kept chuckling when told that observers were breathlessly speculating about what could have happened. Heart to heart meetings? Fist fights?. No, Horford insisted, the team simply had found something while being trapped in each other’s company for nearly seven hours.

The flight featured more talking than usual. More laughing. More camaraderie. But, Horford finally relented, it all traced back to one person.

Kyrie Irving.

"Kyrie was instrumental because he was the one that initiated everything as far as being like, ‘Hey, let’s have conversations, let’s play cards, let’s do this, let’s do that' on this plane ride,” Horford told NBC Sports Boston after Friday’s practice on the campus of UCLA. "And we were all engaged at that point.

"He’s the one who got that ball rolling … We spent a good amount of time together, we talked, we laughed, stuff like that. It just happened to be extended. As opposed to an hour or two hours, almost seven hours. You’d think we’d get sick of each other but, actually, it made the plane ride go quicker. We were just hanging out and talking.”

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To understand just how jarring the change in Boston’s demeanor has been, you have to understand how tense things were before they departed. After the latest underwhelming showing in a loss to the visiting Houston Rockets, only Horford and Irving addressed the assembled media. Irving answered nine questions with a mere 39 words and the final query wondered if the team might rally together on the West Coast trip.

“We’ll see,” shrugged Irving before departing the arena.

Now we know the answer: It did, at least through the early part of the trip. Irving, after huddling with coach Brad Stevens, encouraged teammates to unplug their headphones and amplify their interactions. It was the sort of behind-the-scenes leadership that teammates and coaches suggest often goes unnoticed because Irving doesn’t go out of his way to promote it.

"He’s not going to come out and say it and we’re not coming out and talking about it all the time,” said Horford. "But, yeah, I think that was a big step for our group.”

While Irving has had notable public missteps as he learns how to be the leader of a young roster with big expectations, including publicly pointing his finger at Boston’s younger players amid early season struggles, it’s clear that this team feeds off Irving and his energy.

So Irving’s attempts to get everyone on the same page spoke volumes.

"Basically, it was time for us to wake up, and we know this is an important trip for us to finish out the rest of the season, so I guess Brad and Ky talked,” Terry Rozier told NBC Sports Boston during his weekly interview for Celtics Post-Up. "Ky's our leader and when he's in a great mood and he's feeling good, we're hard to beat and it's contagious. It rubs off on everybody else. Sometimes when he's not like that, it can get everybody uptight. So the way he's been acting has been great, and it's been good for us.”

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Irving seemed like a different person by the time he met with reporters in San Francisco on Monday afternoon. Less than 24 hours after his tight-lipped media session following the Houston loss, Irving spoke for eight minutes on a variety of topics, including how being in the public spotlight can wear on him at times.

But maybe recognizing that the team’s demeanor often reflects his personal state of mind, Irving has gushed with positivity this trip. Even before wins over Golden State and Sacramento, Stevens noted the good vibes permeating the team in the aftermath of traveling west.

Asked Friday what he’s gotten out of the trip so far, Irving noted, "Just some joy. Just having fun playing basketball and competing for one another.”

That’s a particularly notable response considering the way that Marcus Morris had suggested there was a lack of joy in Boston’s play last month. It feels like the interactions on the plane might have helped players work through some pent-up frustrations and allowed the team to put the spotlight back on basketball.

The Celtics responded with a lopsided win over the Golden State Warriors before grinding out a Kyrie-less win in Sacramento. This four-game trip wraps up with a pair of games in Los Angeles against the Lakers (Saturday) and Clippers (Monday).

"I just think it was a positive for our group just to get away and be able to spend a little more time together,” said Horford. "I just think it helped. Sometimes there’s just a lot going on and it’s nice to be able to take a step back and just really focus on playing together and playing basketball.”

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Horford had suggested immediately after the Houston loss that the time out west could benefit Boston. He didn’t know immediately after the plane ride if those conversations would translate into victories but he was encouraged by the team’s state of mind.

"I didn’t know if it was going to be wins and losses. I didn’t know it was going to translate to where we were going to win two games. But I did feel good about our group after that,” said Horford. "I definitely think it has translated in a positive way on the court.”

Horford said the plane ride was just the beginning of the good vibes out west. Players seem to be genuinely enjoying each other and think it’s given the team a much-needed jolt as the playoffs approach.

“We had a really good practice session when we got into San Francisco on Monday,” said Horford. "We had a really good shootaround, and it wasn’t only good from a basketball standpoint but also just us hanging out and being able to spend time together and that’s the most important thing.”

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