“I was watching it the whole way and thought I had a chance once it fell in,’’ said Sweeney, who has hit safely in 16 of the 17 games he has played in. “Peavy threw a good pitch and I got a break.’’

Peavy went after Adrian Gonzalez with five straight fastballs, all up and in. The last one was just enough over the plate for him to ground it into center field for an RBI single.

“He’s a great pitcher and he locates his fastball wherever he wants,’’ said Gonzalez, who played with Peavy in San Diego. “You have to try and cover the plate against him.’’

Thanks to Sweeney running hard out of the batter’s box, the Red Sox scored the only run of the game.

“Real big play,’’ Valentine said. “You don’t know at that time of the game how big a play it’s going to be.’’

Peavy (3-1) otherwise did not allow a runner to second base. He walked one and struck out seven.

Lester (1-2) had a rougher time, needing 122 pitches over seven innings. But he never gave in. He gave up five hits, walked one, and struck out seven.

“He asked what he had to do and I just said, ‘Pitch like an ace. Like Jon Lester is,’ ’’ said Valentine. “And he pitched like an ace.”

Lester had a rough first inning, throwing 32 pitches.

Adam Dunn walked with two outs before Paul Konerko doubled to left field. Cody Ross bobbled the ball and third base coach Joe McEwing tried to wave Dunn in. But Dunn didn’t see him and jogged into third.

Lester got Alex Rios on a fly ball to right field to end the inning.

It was the first of eight consecutive batters Lester would retire. Konerko broke that string with a double to center field with one out in the fourth inning.

Center fielder Marlon Byrd tried to make a diving catch, but the ball hit off his left wrist. No damage was done as Rios lined to center and Dayan Viciedo struck out. The White Sox did not advance a runner into scoring position again until the seventh inning.