What the Celtics learned on the 3-1 swing through the Western Conference

DENVER — The road did the Celtics good to start 2025, and they return home after a successful swing against four Western Conference teams with winning records, one bad quarter away from an undefeated trip.

The growth is evident, especially defensively, where the Celtics were energetic, deliberate and impactful during this stretch, including Tuesday’s road finale, a 118-106 win over the shorthanded Denver Nuggets at Ball Arena.

Denver was missing three-time MVP Nikola Jokic, who tried to warm up hours before tipoff but was sent home with an illness. Shorthanded teams have flourished in recent years against the Celtics, so the game plan was adjusted. Denver was without the league’s most versatile player, so Boston focused on containing Jamal Murray, sending two defenders against him on nearly every second-half possession, playing with the appropriate sense of urgency.

The Celtics needed this win, especially since they were beaten in the final period Sunday in Oklahoma City and wanted to avoid going home on a losing streak. The stakes rise for Boston when the calendar turns to January; it is approaching mid-season. Oklahoma City and Cleveland are trying to distance themselves from the rest of the pack, and the Celtics need to start asserting themselves as they prepare for another long playoff run.

Defense is the first priority. And their emphasis on that side over the last four games was impressive. Of course, the Celtics’ focus on Murray meant that other Nuggets would get an opportunity to flourish, and they did, but eventually the defense took its toll.

“With Jokic out, understand how important Murray is to the game,” Celtics coach Joe Mazzulla said. “Not wanting him to have a big impact has a lot to do with it. For most of the game we were really conscious of switching, which made him play in a crowd against more defenders. And we tolerate some (above average) shooting from the (other) guys, but you have to live with something.”

Murray scored 4 points in the second half and the Celtics allowed Russell Westbrook to dip into the cocoon of his Oklahoma City days with 26 points, but he also committed eight turnovers and was minus-13. The Celtics played an intelligent game, knowing that their talent and strength would eventually prevail. That is an encouraging sign.

Despite coming off a championship and having several veteran players who have been through playoff wars, this Celtics team is far from a finished product. They have improvements to make. The past week was a big step forward.

“Everybody said this road trip was ‘brutal,’ I think is what a few people used,” Mazzulla said. “It was great. I like the way our guys handled it. I like the way we approached it. It was four tough environments and I thought our defense kind of carried us, and our offense is what helped us.”

Mazzulla switched to the intangible, the approach.

“I really like the road trip mindset they brought,” he said. “The physicality that they needed to be was there during all four games. The connection. I think this road trip made us a better team. We just have to keep that going.”

The Celtics allowed 103 points per game during this trip, shot nearly 47 percent from the field and flourished in the other key categories Mazzulla emphasizes. If not for the brutal offensive performance in the second half against the Thunder, the Celtics would have come home unscathed. But the trip was still successful.

“Every game brings a different lesson, and (Tuesday) it was the ability to understand each other and play for each other on the offensive end,” Mazzulla said. “And continue our physicality defensively. Last game it was learning about each other and how to respect each other’s space and be better on the offensive end. The Houston game I thought we answered the call physically and the Minnesota game, it played a great defensive team that has given us problems in a couple of close games.

“I think when you go on some road trips like this, you’re able to get better on and off the field as a team. I thought we did.”

The key to the Celtics moving forward is staying healthy, getting Kristaps Porzingis more integrated and playing more consistently, and continuing to improve defensively as the competition intensifies. But there was a sense of uncertainty as the Celtics embarked on this four-game road trip. They had just been beaten at home by Philadelphia and Indiana before crushing Toronto.

They proved they were ready for this challenge, especially on Tuesday, when the Nuggets made a ton of tough shots and actually tied the game at 93 with eight minutes left before the Celtics cemented the win with a 15-0 run with Jayson Tatum (29 points ) the last two buckets. They were tough enough to withstand the Nuggets offense and savvy enough to outlast an inferior opponent.

“I mean, 3-1 is pretty good,” forward Jayson Tatum said. “We wanted to win every game. We wanted to go 4-0. Sunday was tough, but we came back and responded (Tuesday). Just go home and keep building on this game.”

Gary Washburn is a Globe columnist. He can be reached at [email protected]. Follow him @GwashburnGlobe.