The plan went awry as soon as the baseball left Matsuzaka's right hand. The pitch stayed up instead of sinking down. The barrel of Navarro's bat squarely found the meaty pitch and, next thing you know, the baseball had gone over the wall in left and the Red Sox were on their way to a 5-2 loss to the Devil Rays.

"Since he hit it, I guess it was a mistake," Matsuzaka said through translator Masa Hoshino. "The pitch I threw was a forkball or split-finger. With both teams at zero runs at that point, it was a situation I most wanted to avoid. I'm disappointed I let him hit that ball. Yes, I was going for a swing and miss there."

There would be no grand finale for the Red Sox at the end of their seven-game swing through Cleveland and Tampa Bay. A successful road trip ended with a 5-2 mark and an eight-game lead over the Yankees in the American League East.

Not long after Matsuzaka's lone mistake, the game got out of hand against Manny Delcarmen. The right-hander who had been so good of late surrendered back-to-back homers to B.J. Upton (three-run shot) and Carlos Pena. So a half-inning that began with the teams tied ended with the Red Sox staring at a five-run deficit.

"That's why we went to Manny, so that wouldn't happen," said Red Sox manager Terry Francona. "He threw two [pitches] right in the middle of the plate. Dice-K was so good, his offspeed all day was sharp. He left his split up enough to Navarro. It got away more than we wanted to, in a hurry."

The Red Sox did get back-to-back homers from Manny Ramirez and Kevin Youkilis with two outs in the eighth, but the visitors would get no closer.

Watching the homers by his teammates was a little bittersweet for Delcarmen, who wondered what might have been.

"For the most part, I got a little frustrated because we scored two the next inning, and take away those runs and we're up by one," said Delcarmen. "It just shows that when you make a mistake, they're going to hit it up here [in the Major Leagues]."

Left-hander Scott Kazmir, who has handled the Red Sox in similar dominant fashion in the past, didn't seem to make any mistakes. Before departing with six innings and 97 pitches, he held the Red Sox to six hits and no runs while striking out eight.

"He was striking out everybody, it seemed like," said Red Sox catcher Doug Mirabelli. "He's got that fastball that seems to ride up on hitters, and it's hard to lay off of. He has the ability to strike guys out with a good fastball and a good tight slider."

Matsuzaka (12-8, 3.75 ERA) gave up eight hits and two runs over 6 1/3 innings, walking one and striking out six.

Coming off his 1-0 win over C.C. Sabathia, Matsuzaka came up just short of matching that performance.

"When our lineup is unable to produce runs, I feel that it's my job to hold them to zero runs," Matsuzaka said. "In that sense, I'm very disappointed today."

This was also the first time Matsuzaka had thrown to Mirabelli instead of Jason Varitek, thanks to the 12-inning game on Saturday night.

"I thought they did a good job," said Francona. "They sat down today before the game and Jason sat with him and they did a good job. There were no problems there."

One of the most interesting questions posed to Matsuzaka was how his feel for the baseball right now compares to his final couple of years with the Seibu Lions. The ball used in Japan is said to be smaller and not as slick as the one used in the Major Leagues.

"If my feel for the ball while I was pitching for Seibu was about a 10, I'd give myself about a six right now," Matsuzaka said. "Still, I think the important thing is to pitch well in challenging spots. Of course I didn't want them to hit that home run today, but there's nothing I can do about it now."

Up next for Matsuzaka will be yet another start against Ichiro Suzuki and the Mariners on Saturday night in Seattle. That will mark the fourth time Matsuzaka has pitched against the Mariners.