Houston, TX (Sports Network) - Darnell McDonald's three-run homer came during a four-run eighth inning as Boston toppled Houston, 10-4, in the second edition of a three-game interleague series.
Andrew Miller (2-0) worked six innings for the win, giving up seven hits, two runs and two walks with three strikeouts.
J.A. Happ (3-10) lasted 6 2/3 frames in defeat and was touched for seven hits and five runs while walking three and fanning as many batters.
A four-run eighth inning provided key separation for the visitors against Fernando Abad.
Three straight singles -- from Gonzalez, Youkilis and Josh Reddick -- loaded the bases before Saltalamacchia's sac fly to left plated a run and McDonald followed with a three-run blast inside the left-field pole to make it 9-3.
Youkilis put the BoSox in double digits with a ninth-inning single to bring in Gonzalez, who doubled in the previous at-bat. Matt Downs singled in Bourn during the Houston ninth but it wasn't nearly enough.
The Sox dented Happ for three runs in the first, on a Gonzalez RBI single, an Ortiz walk with the bases loaded and a double-play grounder from Saltalamacchia. The Astros countered in the home portion when Bourn led off with a triple and scored on an Angel Sanchez base hit.
In the fifth, Jacoby Ellsbury doubled inside the first-base bag and scored when Pedroia followed with a double for a 4-1 Sox edge, but Pence hit a solo shot to left to start the sixth.
Navarro followed with a pinch-hit solo homer to left-center for a 5-2 Boston lead in the seventh, and the visitors dodged a bullet in the bottom half as Pence's bases-loaded, two-out walk was the lone damage against a shaky Alfredo Aceves and a steadier Daniel Bard.
Boston has beaten Houston in six of the last eight matchups since June, 2003...The last Red Sox player to hit his first career homer in a pinch-hit situation was Juan Diaz on June 23, 2002...Bourn extended his hit streak to 11 games...After managing only 15 runs in seven games from June 21-29, the Red Sox have exploded for 22 runs during their current win streak.