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BALTIMORE (Reuters) - Japanese starter Daisuke Matsuzaka lasted less than five innings in his seasonal debut for the Boston Red Sox on Saturday as he watched a solid start fall apart in a matter of a few pitches.

The Baltimore Orioles scored six runs in the fifth to overturn a 4-1 deficit and ensure the injury-prone Matsuzaka (0-1) was slapped with a loss after giving up only one hit and one run in the first four innings.

"I think my pitches themselves were pretty good but there are some adjustments I need to make," Matsuzaka told reporters following his team's 12-9 defeat.

"If I'm not able to make those adjustments before my next start, you're going to continue to see negative results."

Dice-K left the mound after giving up seven hits, including two homers, and seven runs over four and two-thirds innings, walking three and striking out four.

"It was kind of a roller coaster," Red Sox manager Terry Francona said. "He starts out, I thought his stuff was excellent. Good slider, good breaking ball. He had some finish on his fastball. (Then) he gets to the fifth."

Matsuzaka, who has been hampered by back and neck problems in recent years, had pitched in the minor leagues in preparation for his return.

"It's a completely different situation and atmosphere, pitching here as compared to the minors," he said.

(Reporting by Gene Cherry in Raleigh, North Carolina. To query or comment on this story email sportsfeedback@thomsonreuters.com)