The teams are scheduled to play a split doubleheader after moving Sunday's game up a day in an effort to complete the three-game series ahead of oncoming Hurricane Irene.
The storm hit the Boston area in the sixth inning, forcing a 45-minute delay. The teams played one more inning before a heavier band of rain began to fall, causing a delay of 2 hours and 15 minutes between the seventh and eighth innings.
Before the deluge, David Ortiz doubled twice and knocked in a pair of runs to extend his hitting streak to 11 games for the Red Sox, who bounced back from a 15-5 loss to Oakland on Friday and won for the fourth time in five games. Mike Aviles chipped in three hits and two runs scored in the victory.
Jon Lester (14-6) went the first six innings for the win, allowing two runs -- one earned -- on three hits with two walks and four strikeouts. He did not return after the initial rain delay and won his third straight start.
Guillermo Moscoso (6-8) was roughed up for eight runs -- seven earned -- on nine hits over four innings in defeat. Brandon Allen homered for Oakland, which had won five of its previous seven entering the contest.
The Red Sox opened the scoring in the home first when Marco Scutaro lined a one-out double off the wall in left, took second on a grounder and scored on a base hit by Dustin Pedroia, who was thrown out trying to stretch it into a double.
Oakland answered immediately when Allen lifted Lester's third pitch of the second inning into the Monster seats for his third homer. Boston, however, countered in the bottom half with a trio of two-out runs.
Josh Reddick drew a walk after Moscoso had retired the first two batters and Varitek belted a homer into the Boston bullpen. Aviles kept the inning alive with a single to right and scored on Jacoby Ellsbury's double off the top of the high left field wall for a 4-1 edge.
After Coco Crisp knocked in a run for Oakland in the top of the third with a sacrifice fly, the Red Sox continued to pour it on with three more in the bottom of the frame. Adrian Gonzalez doubled off the Monster to start the inning and Pedroia walked before both scored on a double by Ortiz. Carl Crawford followed with a sacrifice fly for a 7-2 cushion.
Boston tacked on one more in the fourth when Aviles reached on a bunt single, stole second and scored on a base hit to left by Scutaro. Ortiz doubled to start the home fifth, took third on a fly ball to center and scored on a single by Varitek to make it 9-2.
After the second delay, the A's got a run off Michael Bowden in the ninth when Kurt Suzuki doubled, went to third on a Jemile Weeks single and scored on Cliff Pennington's base hit to right. Crisp flied out to deep right field with the bases loaded to end the game.
Ortiz finished 2-for-4 and is 21-for-42 during his hitting streak...Lester had not allowed a home run in his previous four starts...The Red Sox had a streak of four straight games with at least two homers stopped.