BOSTON – Boston rookie third baseman Will Middlebrooks went out of his way to try to avoid sounding overconfident, considering he has become a hot topic of conversation in a fight for a regular starting spot.

Middlebrooks had a solo homer among his three hits and drove in two runs, Franklin Morales gave Boston another decent start as the fill-in for Josh Beckett, and the Red Sox beat the Atlanta Braves 8-4 on Saturday night.

Middlebrooks, recalled from Triple-A Pawtucket when Kevin Youkilis went on the disabled list with a strained lower back on May 2, has put up big numbers in a small period of time.

“You said it,” he said, smiling, when asked if he is letting his bat do the talking as he challenges Youkilis for playing time. “I don’t care, to be honest. I came here to play baseball.”

Dustin Pedroia added three hits and a walk, and had two RBI for Boston, which won for the eighth time in 10 games to ensure a winning interleague record for the eighth straight season. The Red Sox improved to 10-7 against NL opponents.

But it was Middlebrooks who sparked the offense.

Middlebrooks hit Cristhian Martinez’s first pitch of the third inning into the Monster seats, making it 5-1. It was the ninth homer of the season for the rookie third baseman, who has made it hard for Manager Bobby Valentine to keep him out of the lineup.

“A lot of home-run hitters hit them in bunches,” Valentine said. “You don’t want to take him out of the lineup when he’s hot.”

Middlebrooks has gone 10 for 14 in his last five games with three homers, three doubles and nine RBI, and is hitting .381 in his last 26 games.

“I’m just confident. I feel good right now,” he said. “I’m in a good groove. It’s pretty simple: I’m seeing the ball well.”

Morales (1-1) gave up three runs — two earned — and seven hits, striking out eight and walking one. He fanned a career-best nine in five innings last Sunday against the Chicago Cubs, when he took Beckett’s turn in the rotation after the right-hander had shoulder inflammation.

Morales hopes Valentine gives him another chance to start.

“I feel really confident in myself,” he said. “I think it’s good for me to be starting.”

Valentine quickly answered “yes” when asked if Morales would make another start.

Braves starter Randall Delgado (4-8) was knocked out of the game after retiring only four batters. He gave up four runs and six hits.

“He just didn’t have location,” Braves third baseman Chipper Jones said. “When a young kid struggles with location, it snowballs on him fast.”

Michael Bourn had three singles, two stolen bases and two RBI for the Braves, who lost for the second time in nine road games.

Trailing 1-0 in the first, Boston scored two runs when Adrian Gonzalez had an RBI single, and Middlebrooks followed with a run-scoring double off the Green Monster.

The Red Sox chased Delgado in the second and increased the lead to 4-1 on Pedroia’s two-run double to the gap in left-center. Martinez relieved with the bases loaded and got Gonzalez to bounce into an inning-ending double play.

Bourn’s RBI single cut it to 5-2 in the fifth, but Cody Ross’ RBI double restored Boston’s four-run lead in the bottom of the inning.

Atlanta cut it to 6-4 against Scott Atchison in the seventh, but Brian McCann lined into an inning-ending double play against Andrew Miller with runners on the corners.

In the bottom half, Daniel Nava had a two-run single for Boston.

The Braves took a 1-0 lead in the first on McCann’s run-scoring infield hit. Morales struck out the next two before getting Jones to line out.