Miami Heat Beat Boston Celtics in Game 7 to Advance to NBA Finals

The N.B.A.’s Eastern Conference championship trophy had found its way to the visiting locker room at TD Garden on Monday night. Set atop a couple of packing trunks with metallic trim, the trophy - a sterling silver replica of a basketball - was an attraction for the Miami Heat, who had earned it the hard way with their stunning 103-84 victory over the Boston Celtics in Game 7 of the conference finals.

Players and staff members, clad in N.B.A. finals hats and T-shirts, positioned themselves next to to the trophy for photographs and selfies, memorializing the team’s beautiful struggle before a late-night flight to Denver, where they will face the Nuggets for the N.B.A. championship starting Thursday.

“We never thought it would be easy,” Miami forward Bam Adebayo said.

The Heat’s resurgence as the East’s No. 8 seed has surprised everyone but them. Even when they were scuffling through the regular season, losing nearly as often as they won, Coach Erik Spoelstra stuck with his approach. Spoelstra said they were capable of improving if they continued to focus on their daily work. There was nothing especially sexy about it - meeting after frustrating losses, watching film, practicing hard.

“I think probably people can relate to this team,” Spoelstra said. “Professional sports is just kind of a reflection sometimes of life, that things don’t always go your way. The inevitable setbacks happen, and it’s how you deal with that collectively. There’s a lot of different ways that it can go: It can sap your spirit. It can take a team down, for whatever reason.

“With this group, it’s steeled us and made us closer and made us tougher.”

They will need that toughness against the top-seeded Nuggets, who secured their first trip to the N.B.A. finals by completing a sweep of the Los Angeles Lakers in the Western Conference finals a week ago. The Heat are just the second eighth seed, after the 1998-99 Knicks, to reach the championship round under the current playoff format.

“Everybody’s confidence is so high,” said Heat forward Jimmy Butler, who was named the most valuable player of the series after scoring 28 points in Game 7. “We have belief that we can do something incredibly special. So we are going to hit the ground running when we get to Denver, and I like our chances.”

The Nuggets, who are rested and deep, figure to be the Heat’s toughest challenge to date. At Butler’s postgame news conference, he was asked how he and his teammates planned to slow Nikola Jokic, the Nuggets’ star center and a two-time M.V.P. Butler said he was giving himself until midnight - it was 11:42 p.m. at the time - before he began to think about the coming series.

“I don’t know,” he said. “I’ve got two days to figure that out.”