Celtics' rough play against Sixers led by North Philly native Marcus Morris | Marcus Hayes

It was an obvious message, a macho challenge.

Marcus Morris pushed Ben Simmons in the chest. It happened in the open court, with two officials watching. Simmons took a step back … and just let it happen. No retaliation. No resistance. It happened on the Celtics' baseline late in Game 1 of the Eastern Conference semifinals Monday.

Asked about the incident, Morris interrupted the question.

"You mean the push off?" he said. And he smiled.

Morris stands 6-feet-9, so almost everyone looks up at him. When you do, you see a thick thatch of beard that hides a large measure of malice. If he were a horseman, Pestilence would be his ride.

The Celtics didn't win Game 1, as much as they possessed it: They took the Sixers' lunch money, then shoved their faces in the snow. No one was a bigger bully than Morris, who's beating his hometown Sixers North Philly-style.

"The push off was just a little thing," said Morris, the latest in a long line of Celtics enforcers, which began six decades ago, with Bob Brannum and Jim Loscutoff. "The entire game, we wanted them to know: Nothing is going to come easy. You're going to get bumped. You're going to get hit. You're going to get fouled hard."

And so they were hit, and bumped, and fouled hard.

They were hit, and bumped, and fouled hard again in Game 2 on Thursday night, when they not only surrendered their lunch money but also a 22-point lead.

And guess what happened in the second half?

Morris, 6-9 and 235 pounds, shoved Simmons again. Simmons, 6-10 and 230, took it. Again. The Celtics won. Again.

Guess what's going to happen in Game 3 on Saturday.

Morris was a big reason why Simmons scored just one point in Game 2, and was benched for much of the second half. He was a big reason why Simmons took just four shots, all misses. Morris didn't start either game. He scored 11 points in about 28 minutes in each game. But he is as big a reason why the Celtics lead the series as rookie Jayson Tatum, who is averaging 24.5 points, or defensive savant Marcus Smart, who replaced second-year forward Jaylen Brown in the starting lineup in the first two games. Smart plays hard, but he doesn't have aura Morris carries.

"They feel when I come on the court," Morris said. "They know it's not going to be easy. Down the line, from all-stars to first-year, second-year players."

In case you missed that message, this is Simmons' first year playing. Joel Embiid is an all-star in his second season.

"They know I'm there. You know what I mean? No matter who it is," Morris continued. "It might be the best player. They respect the fact that I'm coming out there. And it's going to matter."

It has always mattered for Morris, who grew up on Erie Avenue. He gave up football for basketball; well, technically, anyway. Marcus and his twin brother, Markieff, played basketball at Prep Charter in Philadelphia, then at Apex Academy in Pennsauken, N.J. He's in his seventh season out of Kansas, and he's not getting any softer.

"I was the toughest player when I was in high school. It's an element of the game each team needs," Morris said. "You've got to have one of those guys who, like, takes no [bleep]. Who'll enforce his will. Who has guys' backs out there."

It's part of a playoff blueprint.

"You look at every team who's been successful in the past," he said. "You have one, or maybe more than one guy that's the toughest guy. Who's going to talk the [bleep]. Foul hard. Still be able to back it up with good play."

And no, Morris doesn't model his game after Dennis Rodman or Charles Oakley or any of the legendary NBA tough guys. It was something in the municipal water.

"I think it's a Philly thing. Think about it," he said. "All the Philly guys. Kyle Lowry: Tough as nails. Dion Waiters: Tough as nails. Rasheed Wallace was tough as nails. Markeiff. I think it's a Philly thing."

Lowry, who played at Cardinal Dougherty and Villanova, runs the Raptors, the No. 1 seed in the East, though they trail the Cavs, 2-0, in their semifinal. Markieff Morris plays for the Wizards, who were eliminated by Lowry & Co., but not before Markieff was fined $25,000 for shoving a referee during a scuffle in Game 3. Waiters, a South Philly kid who went to two prep schools, plays for the Heat, whom the Sixers eliminated in the first round.

The Celtics have never lost a series they led, 2-0. The Sixers have never won a series when down, 2-0. Odds are, Marcus Morris will be representing the city henceforth.

It wasn't only Morris' bruising manner that turned a Sixers rout into a Celtics win Thursday. Smart played like a madman, as usual, and they both got help.

"It changed when Greg Monroe came in," Smart said.

He's right. Monroe, a 6-11, 265-pound center, made his series debut with 8:19 to play in the second quarter and played 6:15. He was on the floor for the first part of the Celtics' comeback run, which cut the lead to 13. Then Morris replaced him, and the lead shrank to 56-51 by halftime.

Celtics general manager Danny Ainge, perhaps the most despised player in the franchise's long history of despicables, built this team this way for a reason. Ainge signed Monroe after the Suns waived him in February. Back in July, Ainge traded for Morris. He signed 6-10, 260-pound Australian center Aron Baynes in July. Both came from Detroit, and both have given Simmons fits; Baynes as a lane-clogging oak tree, Morris as a strong, agile disrupter all over the court.

Whenever Simmons gets close to the free-throw line, Morris' hands are all over him. Whenever Simmons tries to post up, Morris welcomes the grind.

"I feel like I have to play that way, especially in the playoffs. It's physical. That's an element in my game, I enforce for my teams," Morris said. "That's the only way I really know how to play."

The true test of an enforcer is how well he absorbs punishment. Morris passes that test all the time.

When the teams met Jan. 11 in London, Simmons crushed Morris with a shoulder block as Morris prepared to set a pick. A foul was called. Morris jumped up and challenged Simmons … who walked away.

In Game 2 on Thursday, Embiid crushed Morris close to the basket. Morris didn't mind.

"I expect the same thing on the other end," Morris said. "Just know: It's coming from this end.

"No matter what happens."