Red Sox 7, Astros 3: David Ross hit two home runs and had four of host Boston's 17 hits while Ryan Dempster won his first game in a Red Sox uniform.

Ross and Will Middlebrooks hit back-to-back homers in the fourth inning to give Boston a 5-1 lead. Dustin Pedroia had three hits, Mike Napoli drove in his major league-leading 27th run and David Ortiz homered for the second straight game as Boston won for the fourth time in its last five contests.

Dempster (1-2), who received seven runs of support in his previous four starts covering 24 innings, struck out 10 while allowing two runs and four hits in six innings. Erik Bedard (0-2) allowed eight hits - seven for extra bases - and five runs in three-plus innings as Houston lost its seventh straight road game.

The Red Sox scored in the first four innings. Bedard threw 33 pitches in the opening frame, but was only hurt by Pedroia's one-out RBI double. Ross' first homer came in the second inning when he lifted Bedard's 1-2 offering over the Green Monster seats.

Middlebrooks led off the fourth inning and deposited a 3-2 pitch into the Monster seats before Ross followed three pitches later with another shot that sailed out of Fenway Park to put Boston on top 5-1. Ortiz drilled a 2-2 pitch from reliever Paul Clemens into the center field bleachers in the fifth to make it 6-2.

GAME NOTEBOOK: Napoli had two doubles and set team records for two-base hits (13) and extra-base hits (18) in April, while CF Jacoby Ellsbury stole his 11th base to set a Red Sox record for April. ... Boston OF Shane Victorino (back) did not play and has missed four of the last six games. He remains day-to-day. ... Red Sox pitchers struck out 14 Astros.