Jarrod Saltalamacchia homered to back a strong start by Jon Lester, and the struggling Boston Red Sox beat the Chicago Cubs 4-3 on Saturday.

Saltalamacchia, Scott Podsednik and Mike Aviles had two hits apiece for the Red Sox, who had dropped eight of 11. Podsednik and Will Middlebrooks each drove in a run.

Lester (4-4) and the Red Sox were leading 4-0 when the Cubs rallied in the seventh.

Jeff Baker led off with a bloop double and Welington Castillo walked with one out. Then Luis Valbuena belted a three-run homer for his first hit with Chicago.

Lester struck out David DeJesus before Scott Atchison retired Reed Johnson on a grounder to end the inning. Vicente Padilla worked the eighth and Alfredo Aceves finished for his 16th save in 19 chances.

Pinch-hitter Steve Clevenger started the Cubs ninth with a single, but Aceves struck out Bryan LaHair and got Castillo to bounce into a game-ending double play.

Lester (4-4) gave the Red Sox just what they needed on the same day Josh Beckett went on the 15-day disabled list with right shoulder inflammation, the latest in a long line of injuries for Boston.

The veteran allowed seven hits, struck out eight and walked one against a team that came in with a .222 average against lefties, third lowest in the National League.

Jeff Samardzija (5-5) struck out six in 5 1-3 innings for the Cubs after getting roughed up in a loss to Minnesota in his previous start. He was charged with three runs and four hits.

Samardzija was lifted after he issued consecutive walks to David Ortiz and Saltalamacchia. Randy Wells came in, and Middlebrooks drove in Ortiz with a single.

Samardzija's only other glitch was the two-run homer by Saltalamacchia, who was starting in the cleanup spot for the first time in his career. He drove a 1-2 pitch over the wall in right in the fourth.

The Cubs threatened with two out in the sixth, but a breakdown by Alfonso Soriano helped end it.

With runners on first and second, Middlebrooks dropped his hard liner to third. Soriano never bothered to run, though, and got thrown out at first.

A crowd that had seen this type of mental lapse before let him have it on the way to the dugout and when he trotted back out to left field. There were more loud boos when he struck out in the eighth.