Jayson Tatum didn’t hide his frustration after the Celtics lost to the Pacers in the quarterfinals of the In-Season Tournament, which forced them to go home to Boston instead of a free trip to Las Vegas for the semifinals.

“I wanted to (expletive) go to Vegas,” Tatum told reporters in Indiana, flashing a mild smirk. “I didn’t want to go home. I wanted to go to Vegas, so yeah I’m mad. Next year, I guess.”

Added Jaylen Brown: “It’s unfortunate for us that we’re not going to Vegas, but I guess we’ll have to settle for Encore in Boston.”

Certainly, there should be some disappointment for the Celtics as their hopes of claiming the first in-season tournament championship came to an end. It certainly does not replace the ultimate goal of an NBA championship, but the IST proved as something of a playoff simulator. It was an opportunity for growth for a group that’s figuring out how to get over the hump. Not to mention the incentives of a trip to Vegas and a significant cash reward.

But it’s also not the end of the world that the Celtics did not advance. And there could be some benefits to it.

The Celtics, by not advancing, will not be playing an 83rd game they would get if they made the in-season tournament championship. A semifinal matchup on Thursday would have been their 82nd game on the schedule, but the IST championship would not have counted towards the regular season standings. It would have been an extra game that would have carried risk of injury, even if the rewards were significant. Instead, the Celtics receive a home game at TD Garden, where they’re 9-0 this season.

Getting eliminated from the tournament also gives Kristaps Porzingis some extra time to recover from his calf strain that has now forced him to miss four games. With the Celtics’ next game coming Friday, it buys Porzingis an extra day to return for an important matchup against an Eastern Conference matchup.

It also gives the rest of his Celtics teammates some extra rest that’s rare in the midst of a typically packed 82-game schedule. They’ll have three days of rest before Friday’s home game, then another three days of rest before returning to action next Tuesday against the Cavaliers. That gives the C’s some welcomed time off before they hit a busy stretch of their schedule that includes six games in nine days and a West Coast trip that begins on Dec. 19.

What’s the issue?

The Celtics seem to have a third quarter problem.

After leading by seven at halftime, the Celtics were overwhelmed by the Pacers out of the locker room on Monday night. The C’s trailed by as many as 11 in the third quarter and were outscored, 37-23.

It’s become a troubling theme for the Celtics. Among other games, they were outscored by the Magic 29-18 in the third – which included a 17-0 run – of their loss on Nov. 24.

The Celtics have been woeful in the third quarter. They rank last in the NBA with 25.3 points per game and 42.3 percent field goal percentage in the period. All five of their losses this season have come when they lose the third quarter.

How can they fix their issues?

“We have to do something to come out of this locker room better and play 48 minutes,” Derrick White told reporters in Indiana. “It starts with us starters and we gotta be better.”

Not enough credit?

Tatum earned his third career Eastern Conference Player of the Month for games played in October and November after he averaged 27.7 points, 8.8 rebounds and 4.1 assists per game to lead the Celtics to a 14-4 record. The award made Celtics coach Joe Mazzulla reflect on Tatum’s place in the league and how he gets talked about among other stars.

“For him, maybe underappreciated, maybe doesn’t get looked at in the same light as other guys that are up for Players of the Month or Most Valuable Player because of the type of team that he plays on and because of how much of a team player that he is and how much he’s willing to let his teammates strive for us to be a great team,” Mazzulla told reporters. “And so you see guys in other situations where kind of the entire roster and entire team is set up for their individual success, whereas he does a great job of balancing both where he can get you 28, 8 and 5 and he can also be a team player.

“I think that’s really hard to do. I don’t think he gets enough credit for balancing both sides of that coin. His mindset, that’s one of the reasons we have a chance to win year in and year out. He’s one of the best players on the best team year in and year out, and I think he should be more in the conversation throughout the entire season for Most Valuable Player because the value that he brings by being a superstar and at the same time being a great teammate, I think is something that’s really hard to balance and he does great at it.”