Boston Celtics center Luke Kornet, center, dunks against the Portland Trail Blazers during the first half of an NBA basketball game in Portland, Ore., Monday, March 11, 2024.

While the Celtics built the NBA’s most lethal starting five last summer, they faced questions about their bench. Their trade for Jrue Holiday on the eve of training camp was a hit to their talented depth, and they were briefly reminded of that Monday night in Portland as they visited old friends Malcolm Brogdon and Robert Williams, who are both out due to injury.

But despite any outside concerns about their bench, the C’s maintained strong belief in who remained. And as they’ve soared to the top of the league standings this season, that depth has played a big role.

The latest example came Monday. With Holiday and Kristaps Porzingis both sidelined, the Celtics didn’t miss a beat. Payton Pritchard stepped into the starting lineup with a strong effort, Sam Hauser shot the lights out, and the Celtics rolled with ease for a 121-99 victory over the inferior Blazers.

Jaylen Brown led the way with 27 points and Jayson Tatum added 26 points as the Celtics’ stars shouldered the scoring burden but Boston’s reserves carried this victory to the finish line. Pritchard, in his first start of the season, had a near triple-double with 11 points, eight rebounds and eight assists, and Hauser had a season-high 22 points on six 3-pointers.

A game after the bench stepped up for a big performance in Saturday’s win over the Suns, the Celtics continued the theme as they got contributions up and down their roster – from Al Horford to Luke Kornet and Oshae Brissett – in handling the Blazers.

“Really confident,” Hauser told NBC Sports Boston of the bench group. “Our job is to come in and bring energy and do the little things really well, and sometimes we have nights like this where we’re a little bit more involved. We’re always ready when our number’s called and that’s why we put the work in every day.”

The Celtics became the first team in the NBA this season to reach 50 wins, and they still have 18 games remaining. It marked the third consecutive season they’ve hit that win total.

They did so by controlling the game in virtually every aspect. The ball was moving like a hot potato as the Celtics produced 34 assists with just three turnovers, which marked the sixth-most assists with three or fewer turnovers in league history. They were suffocating defensively, and turned stops into 23 fast-break points.

The Celtics were sharp in the details, even against a far inferior opponent on an otherwise mundane Monday night in March. Joe Mazzulla told reporters in Portland that he was pleased with how his team carried some lessons from their film session into the game.

“We’re always trying to find, win or lose, a couple things we’re trying to get better at, a couple emphases. I like that we’re continuing to keep our defensive identity while also trying to grow. …

“Tonight we went 3-2 zone and the guys did a great job executing it, and on the offensive end we had really good carryover from the film session as far as how we need to get better at executing. Regardless of the win or loss, as long as we keep those things, that’s the most important thing.”

The Celtics led by as many as 24 and other than a few brief Blazers runs, they maintained a double-digit advantage for the majority of the night. They hardly had a problem scoring against the young, shorthanded Blazers. Brown went 1-for-8 from 3-point range, but bullied his way inside for easy points. The Celtics went 21-for-25 at the rim as they crushed the Blazers for 60 points in the paint.

Pritchard, who is from the Portland area, made the most of his start in front of friends and family as he controlled the game offensively. But Mazzulla, for a second consecutive game, went out of his way to note Pritchard’s defense.

“The best thing about Payton that people don’t appreciate is his defense and just his tenacity,” Mazzulla told reporters. “We all know he can score, we all know he can shoot, but his level of defensive intensity has been huge for us throughout this year, and he’s really developed a role in his defense and rebounding.”

Hauser overcame a slow start in the first half and scored 17 points in the second half, including four 3-pointers in the fourth quarter that buried the Blazers for good. Portland has been among the league’s best in defending the 3-point line this season, but Mazzulla was happy that a point from film carried to the game. The C’s generated many open looks, and they got Hauser going.

“That was what we talked about today, and how we have to find ways to break down those layers and having an understanding of shot selection at different times,” Mazzulla said. “Guys like Sam are open on the second or third layer of the possession, because you break that down, and I thought Jaylen and Jayson and Derrick (White) and our pick-and-rolls did a great job of breaking down those layers, and getting it to him.”

Initially a question mark, the Celtics’ bench has quieted those concerns. That unit has an average plus/minus of plus-3.3, which is the best mark in the NBA.

Boston’s depth proved its worth again on Monday. In addition to Pritchard, Horford stepped into the starting lineup and scored 11 points – including three 3-pointers in the first quarter – with four assists and three blocks. Kornet was everywhere with six points, five rebounds, two assists, two blocks and several more strong contests at the rim. Even Brissett – who has not seen regular rotation minutes this season – snuck in for four offensive rebounds.

“Top to bottom, you look at Sam, Oshae, Luke, just top to bottom, guys are always ready to play,” Mazzulla said. “From the team perspective, bring the mindset every night and guys are always ready to play.”