BOSTON — If young Joba Chamberlain misbehaves tomorrow night, he might face a spanking from someone else’s Papi.

With Chamberlain scheduled to start for the Yankees in the opener of a three-game series against the Red Sox, David Ortiz yesterday said the talented right-hander should avoid using Kevin Youkilis’ head as a bull’s-eye.

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“None of that, man — just play the game the way it’s supposed to be, and that’s about it,” Ortiz said, referring to Chamberlain.

“This is a guy, as good as he is, the next step for him will be to earn respect from everybody in the league. He’s not a bad guy, but when things like that happen, people get the wrong idea.”

Considering he has fired four pitches either near Youkilis’ head or behind Youkilis in the last 20 months, Chamberlain quickly has emerged as a villain to Red Sox Nation in this rivalry.

There were the consecutive pitches to Youkilis — one of which sailed behind him — in August of 2007 that got Chamberlain suspended. Another close call occurred last July at Yankee Stadium, when Chamberlain threw high-and tight to Youkilis, nearly starting a bench clearing brawl.

Chamberlain uncorked another fastball three weeks later at Fenway that sent Youkilis to the dirt. Angry glares were exchanged.

Why always Youkilis?

“I don’t have an explanation,” Ortiz said.

Talking to reporters at his locker for about 20 minutes between games of yesterday’s split doubleheader against the Twins — the Yankees’ game against the Athletics was on TV in the clubhouse — Ortiz said this weekend will not feel like the normal Yankees-Red Sox circus.

“This one is an easy one — they are missing A-Rod,” Ortiz said.

Though Ortiz considers Alex Rodriguez a close friend, the Red Sox designated hitter said he hasn’t spoken recently to A-Rod, who is continuing his rehab from arthroscopic hip surgery. Nevertheless, Ortiz said he will not miss him this weekend.

“You don’t have the best player in the game in your lineup, it makes it different,” Ortiz said.

But the Yankees are also a different team, having added CC Sabathia, A.J. Burnett and Mark Teixeira since Ortiz last saw them. Sabathia isn’t scheduled to pitch in the series, but Burnett is slated for Saturday’s start.

“The pitching is the biggest move they made,” Ortiz said. “Last year they had good hitters and all of them hit pretty good, but they would score 10 runs and the opposite team would score 12. It’s just not right, you know?

“They let some good hitters go, so they definitely had to go for the good hitter, which was Teixeira. But pitching wise they really needed some help.”

If Ortiz is jealous of Teixeira it’s from what Big Papi has seen of the new Yankee Stadium, where balls are jumping into the right field seats.

“I saw some funky homers that one Cleveland series,” Ortiz said. “I saw some balls going out, that I was like, ‘Oh, that’s a pop up.’ The next thing you know, it was out of there.” mpuma@nypost.com