Matt BarnesBOSTON — Matt Barnes patiently waited as the Red Sox continuously called down to Triple-A Pawtucket for young arms this season. The 24-year-old finally received his opportunity and didn’t disappoint.

Barnes was called up Monday and made his major league debut Tuesday as the Red Sox suffered a 4-1 loss to the Baltimore Orioles at Fenway Park. He tossed three scoreless innings in relief while showing tremendous poise and aggressiveness.

“I think once I actually got out to the mound and into the game, I wasn’t nervous,” Barnes said of any first-game jitters. “I think I was most nervous for my first three or four throws in the bullpen. And then when (the catcher) was down, instincts took over and I wasn’t really nervous at all.”

Barnes entered in the seventh inning with Boston already trailing 4-1. Anthony Ranaudo struggled for 3 1/3 innings before Drake Britton and Burke Badenhop did their best to settle things down. Barnes picked up where the latter two hurlers left off, requiring only eight pitches to record three consecutive outs.

“I think once you get past the nerves and being in front of everybody and who you’re playing against, it’s the same game. I’ve been playing it for 20 years,” Barnes said. “Once you get out there, you kind of don’t really see anything else except for the glove and you just go out there and try to execute pitches.”

Barnes, who induced two groundouts and a popout in the seventh, struck out Chris Davis to begin the eighth. He started the slugger off with back-to-back changeups to jump ahead in the count 0-2 before ultimately recording his first big league strikeout with a 94 mph fastball.

Barnes sat at around 94-96 mph with his fastball Tuesday, though it was his willingness to pound the strike zone and his effective use of all three pitches — fastball, curveball, changeup — that was most impressive. Barnes threw 30 of his 38 pitches for strikes.

“Knowing that I’m not going to go out there and try to give six or seven (innings), I can take the intensity up a little bit,” said Barnes, who was a starter throughout his minor league career before joining Boston’s bullpen.

Barnes ran into some trouble in the ninth inning, surrendering a single to Nick Markakis and a double to Alejandro De Aza with one out. But the 2011 first-round pick rebounded to strike out Adam Jones and retire Nelson Cruz on a lineout to second base — two good major league hitters, obviously — to put the finishing touches on a nice first impression.

“Impressive three innings of work. A high number of strikes. An outstanding changeup,” Red Sox manager John Farrell said. “In the ninth inning, with men at second and third with just one out, he didn’t panic. He used his secondary pitches, particularly in the strikeout of Jones. A very solid three innings from him tonight.”

Barnes had become somewhat of an afterthought as the likes of Brandon Workman, Rubby De La Rosa, Allen Webster and Anthony Ranaudo made their way to the majors and Henry Owens dazzled at Double-A Portland before joining Triple-A. But Barnes sure made a name for himself Tuesday despite Boston’s loss.

Photo via Twitter/@SoxNH