BOSTON (AP) – Bobby Kielty’s tie-breaking single drove in Jason Kendall in the 11th inning on Thursday night and the Oakland Athletics started the second half of the season with a 5-4 victory over the Boston Red Sox.

Kielty stole second and scored on Frank Thomas’ single off Julian Tavarez (1-3) to send Boston to its first home loss in 10 games since June 11. The Red Sox left at least one runner on base in 10 of the 11 innings.

Huston Street (3-3) pitched 1 2-3 innings, striking out two, for the win. Kirk Saarloos got the last two outs for his second save, although he allowed Jason Varitek’s run-scoring single that made it 5-4.

The Red Sox, who played 19 innings in their last game before the All-Star break, led 1-0 and 3-1, but All-Star second baseman Mark Loretta’s seventh-inning error on Kielty’s easy grounder allowed the tying run to score. It stayed 3-3 until the 11th, when Kendall doubled with one out and Nick Swisher, who homered in the third, struck out on a close-call checked swing.

Kielty hit a hard liner off the scoreboard of the Green Monster, and Kendall scored easily. Thomas added the insurance run against Taveras, who worked one inning, allowing three hits and two runs.

Oakland had lost four of five and seven of its previous 10 games. Boston rookie Jon Lester pitched five laborious innings, needing 103 pitches to qualify for what would have been his fifth consecutive victory.

He allowed one run, five hits and five walks while striking out three before leaving with a 3-1 lead.

Craig Hansen pitched a perfect sixth but gave up singles to Antonio Perez and Kendall to lead off the seventh. Manny Delcarmen came on with one out and runners on second and third and got Kielty to hit an easy grounder to second, where Loretta took his eye off the ball and it went by him for an error.

Perez and Kendall scored -the latter run was unearned – to make it 3-3.

David Ortiz was 2-for-4 with two walks.

He doubled to lead off the third and scored on Trot Nixon’s single to give Boston a 2-1 lead. Varitek singled and Mike Lowell, who hit a solo homer in the second, added an RBI fielder’s choice to make it 3-1.

Notes: With the no-decision, Lester can still become the first Red Sox rookie to win his first five decisions since Aaron Sele won six to start his career in 1993. … A’s 3B Eric Chavez, bothered by tendinitis in both forearms, was not in the starting lineup. He has played in just six of the previous 10 games. … The Red Sox purchased LHP Craig Breslow’s contract from Triple-A Pawtucket. LHP Lenny DiNardo was moved from the 15- to 60-day DL to make room on the 40-man roster. … Oakland’s Esteban Loaiza matched a career-high with six walks. … Oakland SS Bobby Crosby singled in the 10th to break an 0-for-21 slump.

AP-ES-07-13-06 2336EDT