Lester (9-3) bested two-time Cy Young Award winner Tim Lincecum, as he walked only one, fanned nine and set down 17 of the last 18 batters he faced to lead the Red Sox to a split of their six-game road trip.
Lincecum (8-3) took the loss after lasting only three innings, the shortest outing of his career. He gave up four runs on five hits while walking three and fanning four.
Boston regained the lead for good in the next half inning when Lester delivered a sacrifice fly to plate Victor Martinez and Scutaro followed with an RBI single to chase home Hall.
The visitors then tallied for a third straight frame on Hall's two-out single that scored Kevin Youkilis.
From that point forward, the southpaw retired the side in order in the fifth, seventh, eighth and ninth innings and did not allow another runner past first base. The only batter to reach over the final five frames was Edgar Renteria after a two-out single in the sixth.
Martinez took a foul ball of his left foot in the third inning and was replaced behind the plate in the fourth by Jason Varitek...The Red Sox improved to 6-1 in games this season against former Cy Young Award winners. Lester has won six of his last seven interleague starts and is 7-2 in his 13 turns versus the National League...Ortiz's long ball was his 275th with the Sox, moving him past Manny Ramirez into fifth place all-time on the team's list...Beltre has hit safely in 15 of his last 16 games...Lincecum is 5-3 in 11 interleague starts...San Francisco fell to 5-3 in series-deciding games. The Giants were 7-8 in interleague play.