Boston, MA (Sports Network) - Pinch-hitter Mike Carp's RBI single in the eighth inning lifted the Boston Red Sox over the Baltimore Orioles, 4-3, in the second test of a three-game series.

Dustin Pedroia tied the game in the seventh with a two-run single. Shane Victorino added an RBI single for the Red Sox, who have won four in a row and lead the Tampa Bay Rays by 2 1/2 games for first place in the AL East.

Boston starter John Lackey allowed three runs on seven hits over 7 1/3 innings. Craig Breslow (4-2) recorded the final two outs in the eighth to pick up the win.

Chris Davis hit his MLB-leading 47th homer of the season and knocked in two runs for the Orioles, who trail Boston by 7 1/2 games in the division. Manny Machado hit a solo homer and scored twice.

Bud Norris got the start for Baltimore and gave up one run on four hits while striking out seven and walking four over 5 1/3 innings. Tommy Hunter (3-3) allowed one run on two hits in the eighth to take the loss.