BOSTON — Even before Boston outfielder Mookie Betts wore a fastball on his hip Monday night, it was abundantly clear that the Red Sox and Orioles are forging the next great rivalry in the AL East.

Their budding feud has everything — star power on each side, bad blood, and the fact that both teams are pretty darned good. At season’s end, they should be sitting No. 1 and 2 in the AL East.

It’s a recipe for entertaining baseball.

Heck, even the managers exchange barbs — a rarity these days.

It didn’t take long for Baltimore’s Buck Showalter to stir the pot this season. With the Red Sox clubhouse battling the flu — a situation that manager John Farrell chatted about often — Showalter noted that his own team was enduring the same thing, but “have done a good job not broadcasting it to the world.”

It was vintage Showalter and indicative of growing friction.

Was Farrell surprised by the dig?

“No,” he said matter-of-factly.

Wanting to beat the Red Sox is encoded in Showalter’s DNA. He’s been firing shots since taking over as O’s manager seven years ago.

Remember the one from 2011 about the Sox payroll? He said: “That’s why I like whipping their butt. It’s great knowing those guys with the $205 million payroll are saying, ‘How the hell are they beating us?’”

The architect of the Orioles also has reason to want to smoke the Red Sox.

Orioles general manager Dan Duquette was the first casualty when John Henry’s ownership group bought the Red Sox in 2002. He then had to watch a bunch of his guys, including Pedro Martinez and Manny Ramirez, break the team’s 86-year championship curse.

That couldn’t have been easy.

But there’s no rivalry unless the teams are good — and this year’s Sox and O’s have talent.

The temperature has certainly been rising since Showalter’s early season jab. Two weekends ago in Baltimore, things almost boiled over.

Two days after Manny Machado slid, spikes up, into Dustin Pedroia, Matt Barnes threw a pitch at Machado’s head. Barnes was slapped with a four-game suspension, and Pedroia was caught on television cameras saying, “It’s not me. … it was them,” referring to his own team.

Pedroia’s pleading didn’t turn down the tension. The war of words continued.

Orioles closer Zach Britton attacked Pedroia’s leadership in an interview with BaltimoreBaseball.com

“Dustin, him telling Manny, ‘Hey, that (pitch) didn’t come from me,’ may be even more frustrating because he’s the leader of that clubhouse, and if he can’t control his own teammates, then there’s a bigger issue over there,” Britton said.

“As a player that doesn’t have the most service time in this room, when a guy like Adam Jones tells me to do something or not to do something, I’m going to do (what he says),” he said. “Same with Chris Davis or Darren O’Day, the guy in my bullpen. If they tell me, ‘Don’t do this or that,’ I’m going to listen to them because they’ve been around the game and they’ve seen things I haven’t seen. And you respect their leadership.”

The nastiness was compelling. Asked about his comments Monday, Britton backed off a bit but didn’t offer any words of apology to Pedroia.

“Dustin reached out to a veteran player on our team about the comments — just wanting to clarify some things,” Britton said. “Once we did that, I think we’ve turned the page and moved on.”

Showalter claimed he wasn’t anticipating any fireworks this week at Fenway, but Betts did end up getting drilled by a 94 mph heater Monday night. It may have been inadvertent; righty Dylan Bundy struggled with his command. But there was no denying the result.

“I know the respect that our guys have for their club. I think if you really took a poll, people are looking forward to playing baseball against a really good team,” Showalter said before the game. “I know they have that same respect. The players, I think the people involved may look at it a little differently. Maybe I’m naive about it. But I know how our guys feel.”

Monday’s game, a 5-2 Orioles win, was reportedly marred by racist taunts from fans directed at Baltimore outfielder Adam Jones, who told MLB.com that a bag of peanuts was also thrown in his direction while he was on the field. The Red Sox issued a public apology Tuesday morning, saying the organization was “sickened by the conduct of an ignorant few,” and that “no player should have an object thrown at him on the playing field, nor be subjected to any kind of racism at Fenway Park.”

Notwithstanding the shameful conduct of a few fans, a fresh rivalry is good for everyone — fans, players, the game of baseball. There’s a reason that ESPN recently decided to make last night’s game a national broadcast.

This new feud is now must-see TV.