Updated

BOSTON (Reuters) - Boston slugger David Ortiz smacked a two-run home run and Japanese starter Daisuke Matsuzaka shook off a slow start as the Boston Red Sox came from behind to beat the Oakland Athletics 6-4 on Wednesday.

Trailing 3-0 in the first inning, Kevin Youkilis hit a two-run single and Ortiz's blast provided a 4-3 lead for the Red Sox, who scored six unanswered runs with late RBI hits from Dustin Pedroia and Marco Scutaro.

Matsuzaka, who allowed three runs in the first innings, completed 6 2/3 innings while striking out seven batters.

The Japanese started the season on the disabled list with a neck injury and has been inconsistent this season. He walked eight batters in his last game.

"I was thinking during my previous outing that if I'm going to give up all those walks, I'm better off just trying to let them hit it," Matsuzaka told reporters through an interpreter.

"Considering what happened in my last outing, yes, I wanted to be more aggressive about throwing strikes."

Closer Jonathan Papelbon pitched the ninth where he allowed a pinch-hit home run to Kevin Kouzmanoff, but still earned his 13th save of the season.

The Athletics grabbed their three-run advantage on Wednesday on an RBI double from Ryan Sweeney and a two-run homer by Kurt Suzuki who finished 2-for-4.

(Editing by Greg Stutchbury)