There was no question about it -- Matsuzaka was slumping. He had given up a generous 20 runs over his last three starts. He owned a 9.57 ERA over his last five. His numbers after five days of rest, the gold standard in Japan, were markedly better than on four days, the typical gap between starters in a five-man Major League rotation.
Friday night was the test case, the Yankees' offense -- baseball's most patient and powerful -- the variable. Dice-K stubbornly held steady.
"I thought he pitched with a lot of heart," said Red Sox manager Terry Francona of Matsuzaka, who gutted out 5 2/3 innings of two-run ball over 120 pitches. "I thought he made himself use all his pitches. They made him work hard, as we did with [Yankees starter Andy] Pettitte. But I thought he did a good job."
"When he left the game," Francona added, "we were in good shape."
Francona spoke previously about incorporating more of Matsuzaka's offspeed pitches into his game plan. That didn't mean abandoning the fastball, which Matsuzaka employed on Friday with varying degrees of success.
Some fastballs missed the zone wide and high, leading him to face patient Yankees like Hideki Matsui and Jason Giambi in hitters' counts, or walk them with less than two outs. Control of his breaking repertoire wasn't much better during a game in which he issued five free passes.
Time and again, though, Matsuzaka unleashed big pitches when and where it counted, striking out Alex Rodriguez on high fastballs to end the third and fifth innings.
"He got out of jams," Red Sox third baseman Mike Lowell said. "I don't think he was as efficient as he would've wanted to be, because I think we would've allowed him to go deep in the game. But he made pitches when he had to, and he gave our team a chance to win, that's for sure."
Mike Timlin relieved Matsuzaka in the sixth after Dice-K loaded the bases with a pair of walks to Matsui and Melky Cabrera. Matsuzaka wiped his brow, then removed his cap before an appreciative Fenway Park crowd as he left the field.
After the game, Matsuzaka defused speculation about fatigue with characteristic humility.
"I probably wasn't worried as much as what some others were thinking or saying," he said. "I think it's a fine line between being hit and not being hit, and I just tried my best to be on the right side of that line today."
"I wouldn't say that my pitching was consistent or stable throughout," Matsuzaka added. "What I wanted most of all today was the win, so I was focusing a lot more on the result today."
Alex McPhillips is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.