Al Horford comes from the Dominican Republic, and he lives in Boston, but he also owns real estate inside Joel Embiid’s head.

Embiid needs to evict him if the Sixers hope to make noise in the postseason the next two seasons.

That’s because Al Horford is signed through next season.

On Tuesday, Horford and the Celtics beat the Sixers, 112-109, at the Wells Fargo Center for their third win in the teams’ three matchups this season. Embiid has played the Celtics 12 times in three seasons, including the playoffs. He has won twice.

Horford has played him each time. He has played him well.

“He’s not doing anything. It’s just on me," Embiid said after Tuesday’s game. "I was sleepwalking for three quarters, and that’s on me. It has nothing to do with anybody.”

Sure about that, big guy?

In Embiid’s seven career regular-season games against Horford and the Celtics, his scoring average (22.1) is nearly two points under his career average, and his field-goal accuracy (43.5 percent) and three-point shooting (22.6 percent) are his second worst against any team he’s faced more than five times. Embiid is 1-6 in the regular season against them. The numbers are similar in the five playoff games: 23.0 points, 44.1 percent from the field, 23.8 percent from three-point range.

Embiid’s worst matchup? Memphis and Marc Gasol.

The Toronto Raptors just traded for Marc Gasol.

Certainly, every great player faces certain players, great or otherwise, who limit them: LeBron James vs. Andre Iguodala, Kobe Bryant vs. Tony Allen, Michael Jordan vs. Joe Dumars. It’s not as though Horford — or Gasol, for that matter — wins games against the Sixers by completely muzzling Embiid.

Joel Embiid reacting to a non-call against Al Horford during the fourth quarter.
STEVEN M. FALK / Staff Photographer
Joel Embiid reacting to a non-call against Al Horford during the fourth quarter.

It’s just that Embiid is so dominant and so versatile that limiting him repeatedly is a remarkable feat, and one that clearly frustrates him. Still fuming over a non-call on Horford with 33 seconds to play, Embiid snatched the mic off the table at his postgame press conference and growled:

“The referees [bleeping stink]."

They were not alone.

Embiid scored 23 points, more than four fewer than his season average. He hit 9 of 22 shots, 40.9 percent, almost 8 percent worse than usual. He hit just 2 of 8 threes, about 5 percent worse than his average. He also committed five fouls, so when Marcus Smart dunked on him on the next play and gave the Celtics a four-point lead, Embiid did not challenge.

(Smart then scowled, and appeared to ask Embiid if he had an “itch,” or maybe if he was “rich.” It was hard to tell.)

Embiid might be right — the refs might have been bad — but the refs didn’t face the hindrance of Horford.

And it isn’t all Horford. He has always had the advantage of a deeper team and a brilliant coach. It takes a village to stop The Process.

And it’s easy to understand Embiid’s irritation.

Al Horford doesn’t look a player built to stop Embiid. Al Horford looks like the MVP of a 35-and-over rec league.

Embiid is 7-foot-2 and weighs 280, which makes him 4 inches taller and 35 pounds heavier than Horford. So, how does Horford do it?

“Honestly, I just try to contain him the best that I can,” Horford said. “He’s too good of a player. The guy can do it all. My whole thing is, always, making sure I’m in the right place at the right time. Make sure I contest as much as I can.”

It helps when the Celtics make Embiid work to guard Horford, a two-time national champion at Florida and a five-time All-Star who made the all-defensive second team last season. That’s where Celtics coach Brad Stevens came into play.

“Tonight, we really played a lot through me,” Horford said.

That’s not always necessary. Not on a team with second-year star Jayson Tatum, former All-Star Gordon Hayward, third-year swingman Jaylen Brown, and, of course, point guard Kyrie Irving, who missed Tuesday’s game with a knee injury. Irving missed the playoffs last year, too, but the Celtics didn’t miss him in the second round against the Sixers, whom they beat, four games to one. Tatum got much of the credit, but it was Horford who carried them.

“Against these guys, he’s critical,” Stevens said Tuesday.

And he was clinical. It was one of the rare games in which his stat line was better than Embiid’s. Horford finished with 23 points on 9-for-16 shooting, hit three three-pointers and collected four steals.

A couple of those steals came against Embiid.

Embiid thinks Horford got away with highway robbery, at the 33-second mark. Horford disagreed.

“When he swept? That’s tough," Horford said earnestly. After Embiid initiated contact, Horford gave ground and flung his arms high to avoid further contact. “I didn’t think it was a foul,” he said.

Horford then invoked the balance clause: He said he was the victim of a debatable call with 2:11 to play, when Embiid put his forearm into Horford’s chest, pushed him to the floor, and scored.

“A few plays before that, I thought it was a charge,” Horford said. "They called a block."

Unlike Embiid, Horford did not curse about the refs. But then, unlike Embiid, he’d won. Again.

He’d won in a place that he sometimes calls home.