Becoming a tough team doesn't happen overnight. However, the Boston Celtics are trying to demonstrate their resilient mentality during a difficult stretch of the 2023-24 season.

On Tuesday night, the Celtics were forced to put that sturdy mindset to the test against a stubborn Indiana Pacers team. Although Boston scored a season-high 81 points in the first half, it saw its 20-point lead disappear in the third quarter. Once Indiana retook the lead, the game turned into a true battle.

Thanks to some clutch defensive play from Celtics starters Derrick White and Jayson Tatum, Boston held on for the 129-124 win. Center Kristaps Porzingis commended his team's effort in the hard-fought victory versus the pesky Pacers, who had already beaten the C's twice this season.

“We just had to turn it up a notch,” Porzingis said. “And we have to stay high-energy and strong mentally on tough nights like this on back-to-backs. We might be tired but we have to put all that stuff and all those excuses to the side and just play hard and play to our level.”

Like Porzingis said, there are few excuses for the talented Celtics. They had all five of their starters finish top 10 in All-Star fan voting and have a real chance at sending at least three of their guys to the All-Star Game in Indianapolis. Even on the second leg of a back-to-back, the league-leading C's need to compete every night to fend off hungry teams eager to dethrone them.

“You always want to have a pretty game,” Porzingis said. “You want to hit the shots and boom-boom-boom everything's perfect. We're getting all defensive stops and rebounds, but it's especially tough against this team … But we responded, especially our second unit … This was a real full-team effort.”

Although Boston was crushed on the offensive glass, it never surrendered. And when the game became a one-possession contest with 1:04 left in the fourth quarter, the Celtics buckled down and got crucial stops when they needed to.

Celtics' growth evident in close win vs. Pacers

Last season, this could've been a game Boston dropped after being up big—and Celtics star Jaylen Brown admitted it.

“In those moments of adversity, we've still found ways to win. I guess everybody wants us to be perfect over the course of 82 [games]. It's tough to do,” Brown shared. “I think we've taken our steps this year. Because I think a lot of those times, you know, we've blown leads and they've ended up in losses.”

So, what's changed for the Celtics during the 2023-24 campaign? According to Porzingis, Boston's toughness stems from head coach Joe Mazzulla and his ability to challenge his players.

“[Mazzulla] definitely challenges guys, and that's a great thing,” Porzingis revealed. “I think also you have to give credit to [Tatum], [Brown]. He can challenge those guys and if he can challenge those guys then he can challenge everybody else also. You have to give credit to JB and JT for being open to that. And that's a big part of what makes us a great team and we need that in the long run and the most important moments in the playoffs when some high-tension situations will come.”

While the playoffs will be the ultimate test of toughness, the Celtics have already been in some high-pressure situations. They came back from down 21 to avoid handing the Detroit Pistons their first win in over two months, they dazzled in overtime to defeat the Western Conference-leading Minnesota Timberwolves, and erased a 17-point deficit to triumph over the New Orleans Pelicans on Monday night.

But, perhaps the most impressive example of Boston's resiliency is its NBA-best 10-1 record in games following a loss.

“For the most part, we've been a physically tough, mentally tough team. And I think it's important that we haven't skipped any steps,” Brown said. “It's a tough moment, guys are out at a tough part of the season mentally for everybody. I think we've been responding well.”

Of course, the Celtics haven't been perfect. They suffered an embarrassing collapse to the Charlotte Hornets early in the season and came up short in the clutch to the reigning champion Denver Nuggets in mid-January. As Brown said, no team is going to dominate all 82 games, so the Celtics still have work to do.

If you're Boston though, you have to like where you're at. The Celtics sit atop the Eastern Conference with a league-leading 37-11 record, which puts them 4.5 games ahead of the second-place Milwaukee Bucks.

Yet, for the C's to truly prove their mettle, they'll have to do it in the postseason. Per usual, it's championship or bust in Boston, but this pressure is nothing new for the 2023-24 Celtics.