BOSTON — As hard as he tried, Jarrod Parker couldn’t quite stop a grin from coming to his face in Oakland’s locker room.

He was entitled to a little emotion after keeping his composure while shutting down Boston’s resurgent offense and picking up his first major league win when the Oakland Athletics beat the Red Sox 5-3 on Tuesday night.

“It’s pretty cool,” Parker said between grins. “I don’t think it will set in until maybe tomorrow or when I’m fielding phone calls later tonight.”

The 23-year-old right-hander scattered four hits over 6 2/3 innings, holding Boston to just a run one night after the Red Sox racked up 11 runs on 11 hits off Oakland pitchers.

The few times Parker got in trouble, he quickly got himself out of the threat before it could get worse as the A’s evened the three-game series 1-all on a frigid night at Fenway Park.

“As long as he throws the ball over the plate with his stuff, he’s going to have some success,” Oakland Manager Bob Melvin said. “I don’t want to say you worry, but you really want to see how a young pitcher like that handles his first time at Fenway Park and he handled it beautifully.”

Jemile Weeks ended on 0-for-12 slump with a leadoff single and finished 2 for 5 with two RBI and two runs scored for the A’s, who ended a three-game losing streak.

Oakland scored the first five runs and provided plenty of security for Parker (1-0), who was making just his third start in the majors.

Parker was recalled from Triple-A Sacramento last Wednesday and got a no-decision against Chicago that night. Parker struck out four, walked two and hit a batter before getting pulled in the seventh inning.

Parker said he just followed catcher Kurt Suzuki’s lead and didn’t try anything fancy.

“I don’t think we threw more than five or six breaking balls. Just going at guys moving the ball in and out was effective tonight,” Parker said.

Boston starter Felix Doubront (1-1) wasn’t nearly as effective. He threw 30 pitches in the first inning alone and struggled through four innings. He struck out eight, but also allowed six hits, walked two and threw two wild pitches while allowing five runs.

The Red Sox had just four hits until Cody Ross led off the ninth with a double to left off of Grant Balfour. Marlon Byrd singled with one out, Punto walked to load the bases for Mike Aviles, who lined a single to center and cut Oakland’s lead to 5-3.

Jordan Norberto came in for Oakland and got the save, striking out Lars Anderson and getting Dustin Pedroia to ground out to second.

It was Norberto’s first save in the majors, leaving the A’s in a bit of a quandary deciding whether the reliever or starter would get the game ball.

“I don’t know who has the ball,” Parker said. “We might have to cut it in half.”