BOSTON -- The manager left one game with nosebleeds. The designated hitter left another feeling dizzy.
"That's right," said A's designated hitter Frank Thomas, who singled in the second inning before leaving Sunday's game with a racing pulse and dizziness. "We'll take it."
The A's took the series from Boston and left the Red Sox with a half-game lead over the New York Yankees in the AL East. Oakland, which had lost three straight before coming to Boston to start the second half, opened a one-game advantage in the AL West over the Texas Rangers, who lost 4-0 to Baltimore.
On a humid, 93-degree day with little wind, Blanton (9-8) allowed just Alex Gonzalez's solo homer in the fifth and struck out four while walking two. The heat took Thomas out of the game; after splashing cold water on his face, he lined a ball off the Green Monster in the second inning, but he lumbered to first base and wasn't able to take second, even though left fielder Manny Ramirez had trouble coming up with the carom.
"I don't even know how I hit it," said the 38-year-old two-time MVP. "I'm not a kid anymore. I have to be careful."
Thomas reported to A's manager Ken Macha that he was dizzy, and Macha sent up Nick Swisher to pinch hit in the fourth.
"I said, 'What else is going to happen,"' said Macha, who had to leave Friday night's game when the training staff couldn't stop his nose from bleeding.
Kyle Snyder (1-1), making his second start for Boston since being claimed on waivers last month, cruised through four shutout innings but couldn't make it out of the fifth. He allowed five runs -- all in the fifth -- eight hits and a walk, striking out six in 4 2/3 innings.
"He put himself in real difficult situation to pitch out of," Boston manager Terry Francona said. "I thought up to that point he had done a real good job."
Jason Varitek went 2-for-4 in the game and 6-for-15 in the series after just three hits in his previous 35 at-bats.
Although Marco Scutaro made two errors at third base, he also made a nice stop on Kevin Youkilis. Jay Payton added a couple of nice catches in right field.
"There weren't too many easy plays," said Blanton, who went 7-5 with a 2.65 ERA after the All-Star break last season and is on the same track this year. "I could go around the whole diamond."
Said Red Sox centerfielder Coco Crisp: "It's one of those games where we couldn't put the ball in the right spots. They made some nice plays, but we hit some balls hard."
Jason Kendall had three hits for the A's. Kotsay was 10-for-18 in the series to raise his average from .246 to .263.
It was a scoreless game until the A's sent 10 batters to the plate in the fifth. Adam Melhuse tried to bunt but Snyder hit him instead, loading the bases with nobody out. Scutaro walked to drive in one run, Kotsay drove in a pair with his single, and Swisher and Payton each had RBI singles.
After Gonzalez made it 5-1, the A's added three insurance runs on Mark Ellis' double, Kotsay's single and Payton's sacrifice fly.
- The Red Sox recalled Snyder from Triple-A Pawtucket to start the game and sent LHP Craig Breslow to Pawtucket to make room for him.
- The A's won a series at Fenway Park for the first time since August 2003.
- Olympic snowboardcross gold medalist Seth Wescott threw out a ceremonial first pitch.
- Varitek caught his 990th game, tying Carlton Fisk for the lead on the Red Sox's career list.
- Hall of Fame spokesman Jeff Idelson was at the game to meet with Red Sox reliever Keith Foulke over the spikes he wore in the 2004 World Series.