BOSTON — Jaylen Brown clapped his hands together a couple of times before walking off the court with two minutes left Tuesday night.

If the Boston Celtics star felt any anger after he and the starters were pulled from a 111-97 Game 2 loss, which evened their first-round series with the Philadelphia 76ers, he didn’t show much. He has been around long enough to understand the ups and downs of a postseason run.

“It’s the playoffs,” Brown said. “Welcome to the playoffs, you know what I mean?”

For the Celtics, the loss had to have felt that way. Until Tuesday, they had been on a joyride. Nobody expected them to be great this season, but they exceeded all those expectations to enter the playoffs as the second seed in the Eastern Conference. They then rolled the 76ers easily enough in Game 1 that many thought the series would be a snoozer.

After getting outclassed in Game 2, including being outscored 20-8 over the final 5:39, the Celtics aren’t playing with house money anymore. They are now a heavy favorite in danger. Widely regarded as a title contender, Boston lost homecourt advantage to a 76ers team without Joel Embiid (appendix). The Celtics were wiped out by Tyrese Maxey down the stretch Tuesday, setting up an uncomfortable couple of days for them before Friday night’s Game 3 in Philadelphia.

“I’m looking forward to it,” Brown said. “I’m looking forward to the film session. We’re still learning and growing as a team, so these opportunities you can look at it as a negative or you can look at it as a positive. So we’ll learn from it and then we’ll get back to Celtics basketball.”

Of course, Brown has been in such situations before. He could have ripped his team apart Tuesday. He is not afraid to send a harsh message if he considers it appropriate, and he believed the 76ers outcompeted the Celtics. Instead, Brown acknowledged his disappointment while striking an optimistic tone.

“We’ve just got to continue to have the right mentality and have each other’s back, and just breathe,” Brown said. “At the end of the day it’s basketball, but you’ve got to still play with a force. We can’t allow the other team to take advantage of us, in a way, offensively or defensively. So, it’s going to be a journey. It’s going to be some ups and some downs, but I’m looking forward to it with my guys.”

Until Tuesday, the Celtics’ journey was one of warm sunshine and delicious candy. They were set up for a significant drop off, but Brown, Derrick White, Payton Pritchard and coach Joe Mazzulla wouldn’t let that happen. They lacked proven players in the supporting cast, but developed one of the deepest rosters anyway. It was far-fetched to expect Jayson Tatum to play at an All-Star level after returning from a torn Achilles, but he did, elevating the team to greater heights after he came back in March.

The Celtics experienced their most basketball adversity early, when they started the season on a three-game losing streak. They bounced back quickly enough that the emotions of that stretch never lingered. From there, they became a rocket ship climbing higher and higher. Several players have stated how much they have enjoyed this season, including Brown, who has done so repeatedly.

Brown has plenty of reason to believe in his team. After Game 2, he chose to focus on that.

“I trust our group,” Brown said. “We’ve grown a lot over the course (of the season). Obviously this is the ultimate test, playing in the playoffs, and we’ve got players who have gotten better and developed, and we’re gonna rely on them. I trust them to come out and make those plays and contribute to the game.”

Philadelphia's Tyrese Maxey dives for a loose ball in front of Boston's Jaylen Brown.

Tyrese Maxey had Jaylen Brown and the Celtics off-kilter in Game 2. (Adam Glanzman / Getty Images)

Moving forward, the Celtics will need to do a better job of limiting the 76ers backcourt. Maxey and VJ Edgecombe, stifled in the series opener, operated with more freedom while combining for 59 points in Game 2. Though Tatum pointed out that Maxey only shot 11 for 28 from the field, the Philadelphia duo delivered timely baskets throughout the game. After Boston pulled within 91-89 midway through the fourth quarter, Maxey drained consecutive 3-pointers to fend off the charge.

“Maxey just walked into two big threes back-to-back when we had cut the lead to two,” Brown said. “So we’ll watch it and see what we can be better at there. But that was two big momentum plays that helped them pull away.”

Maxey then essentially finished off the Celtics with an and-one reverse layup to put Philadelphia ahead 108-92 with 2:42 left. Mazzulla subbed out his starters for good less than a minute later.

The Celtics actually came out with the right mindset early in Game 2, playing with a nasty edge for most of the first quarter. Early in the game, Brown stared at Adem Bona after unleashing a powerful dunk on him. Though he picked up a technical foul for the taunt, his attitude reflected Boston’s impressive aggression. The Celtics played well enough while surging ahead 26-13 that 76ers coach Nick Nurse instructed his team to just hang on.

“I thought they were spectacular to start,” Nurse said. “I mean, they were flying. They were making everything. They were just running in to jump over everybody for rebounds. And I just said, ‘Listen, you’re pretty solid down there.’ I said, ‘They’re great right now and let’s believe that they’re not going to be this great the whole game and just hang in there.’ And our guys did.”

Unlike in Game 1, when the Celtics added to their lead in every quarter, the 76ers fought back in Game 2. Andre Drummond, who failed to grab an offensive rebound in the series opener, batted in a putback layup late in the first quarter. Shortly afterward, Quentin Grimes splashed in a 3-pointer and Maxey intercepted a Payton Pritchard pass for a fast-break layup the other way. The 76ers ended the first quarter with another second-chance basket to cut Boston’s lead to 28-25.

Edgecombe, who finished with 30 points and 10 rebounds, then dominated the second quarter with 16 points as the Celtics fell behind 62-54 going into halftime.

“I think the second quarter we gave up 37 points,” Tatum said. “Doing that in a playoff game is tough. It’s not a recipe for a win and you got to give them credit. They played better, obviously, and that was to be expected. Some live ball turnovers, some offensive rebounds that we gave up and then obviously, when you’re not hitting shots, it just puts more pressure on your defense. That’s kind of what happened tonight.”

Like Brown, Tatum didn’t sound too down after the loss.

“Playoffs are a roller coaster,” Tatum said. “I think what I’ve learned throughout my nine years in the playoffs is just stay even-keeled throughout, right? And I think the team that sticks together and does that from an emotional standpoint will be fine.”

The Celtics have stayed together all season, but until now, they never had pressure pulling on them like this.