BOSTON -- Through four innings, Red Sox righty Kyle Snyder was looking like he could be the ace of any staff in baseball, and not the No. 5 starter that Boston called up from Triple-A Pawtucket. Unfortunately for Snyder, the rules of Major League baseball guaranteed that at least five more innings would be played on this sweltering Sunday afternoon against the A's in a game the Red Sox ultimately lost, 8-1, at Fenway Park.

Snyder held up his end of the scoreless pitchers' duel with A's pitcher Joe Blanton for the first four innings before unraveling in the fifth. Snyder began the inning allowing two singles, hitting a batter and walking in Marco Scutaro for the first run of the game. Snyder allowed a hit to the lead-off hitter in every inning.

"I ran into some trouble," Snyder said. "I left a couple balls up and gave up a couple of base hits. The hit batsman really cost me that inning, under the circumstances. They were looking to give me an out with a sacrifice bunt, and I hit him and wind up with the bases loaded and nobody out. Just not the best inning."

It appeared as if Snyder might rebound, as he struck out Jason Kendall and Mark Ellis with the bases loaded. However, Snyder's day came to an end when he gave up a two-run single to Mark Kotsay and an RBI single to Nick Swisher.

"Well, he started out the game, and it looked like that his command wasn't where he wanted it to be for the past couple of innings," Red Sox manager Terry Francona said. "[He] just put himself in a real difficult position to pitch out of. Up to that point, he had done a pretty good job."

Rudy Seanez came on to finish the inning, surrendering an RBI single to Jay Payton before getting Bobby Crosby to ground out.

Snyder finished the day having allowed five runs on eight hits over 4 2/3 innings. He matched a career high with six strikeouts, a feat he has accomplished in both of his starts for Boston. Snyder didn't duplicate the win he achieved in his Red Sox debut, but the much-lauded Boston offense didn't provide much support.

"Well, today it seemed that we were out on the field more than the dugout," Francona said. "Heat doesn't help. I think we are a good hitting team, and all good teams go through it a couple days -- whatever it is.

"I thought Blanton got something on his fastball, with a good changeup, and [he] threw in some breaking balls. We didn't have very many opportunities, and when we tried to, their defense played well, [even] spectactular at times. [They] didn't allow us to get something going."

The lone run of the day for Boston came on a solo home run by Alex Gonzalez that cleared the Green Monster in left field in the fifth inning. It was Gonzalez's sixth dinger of the season. Amassing only six hits, scoring opportunities were few and far between for the Sox, and when chances did arise, they could not take advantage.

After Mark Loretta and Manny Ramirez reached base in the first inning, Trot Nixon ripped a bullet to the right side of the field, but Ellis made a diving grab and throw to end the inning.

With the Red Sox down, 5-1, in the sixth inning, Ramirez drew a two-out walk, but he was gunned down by Kotsay at third base, as he needlessly tried for an extra base on a Nixon single.

"I think the good news is, it looks like his knee feels good," Francona said. "He's done that a couple times now. The timing probably wasn't the best in the world, but I do like when he's aggressive. I just would love to see [Mike] Lowell have a chance to hit a three-run homer."

The A's scored three more runs off Julian Tavarez in the ninth to cap off the offensive onslaught.

"What Julian does every day does not go unnoticed. He takes the ball," Francona said. "I want to say, in the last three days, he has thrown about 85-90 pitches, and he takes the ball no matter what the situation."

The Red Sox lost three of four to the A's and have now dropped four of their last five games and seven of their last 11. After the Yankees' three-game sweep of the White Sox, the Red Sox now hold only a half-game lead over the Yankees for first place in the American League East.

"That's the way it's gonna be," outfielder Coco Crisp said. "It's gonna be close throughout the remainder of the year, and, hopefully, we just finish up on top."

Sunday's game marked the 990th career game caught by Jason Varitek for the Red Sox, tying a team record held by Carlton Fisk.