Lester threw 106 pitches and allowed 10 hits for just the second time in his career. The only other time he gave up that many was last April 19 versus Texas. He also lost two games in a row for just the second time in his career.

Lester also struggled in his season debut, a 7-2 loss to Tampa Bay at Fenway on Wednesday, allowing five runs on eight hits in five innings.

Meanwhile, Dallas Braden (1-1) picked up the win for the A's, allowing two runs on six hits in six innings.

Kevin Youkilis' second home run of the season, a blast to left field, gave the Red Sox a 1-0 lead in the second inning.

It was all Oakland after that.

Oakland (3-4) scored five times in the fifth inning, the big hits a two-run double by Jason Giambi and a solo homer by Jack Cust. Matt Holliday and Orlando Cabrera knocked in the other runs with singles.

Nomar Garciaparra gave the A's a 6-1 lead with a line-drive homer to left field in the fifth.

The Red Sox got one run back in the sixth when Rocco Baldelli scored on David Ortiz's single to center.

With two out in the seventh, Holliday drove in Giambi with a triple to right off Takashi Saito. Giambi reached after being hit with a pitch by Javy Lopez.

Bobby Crosby delivered Oakland's eighth run with a sacrifice fly in the eighth, scoring Cust.

Youkilis, who also had a double, was 2 for 4 and is batting .519.

Boston will send Daisuke Matsuzaka (0-1) to the mound tonight against Oakland left-hander Dana Eveland (0-0).