HOUSTON -- The beginning of Saturday night’s game could not have gone much worse for Red Sox starter Andrew Miller.

Michael Bourn clouted his second pitch for a triple to left-center. And then Miller barely escaped physical injury on line-drive singles up the middle by the next two Houston hitters, Angel Sanchez and Hunter Pence.

Thankfully for Miller, he had a 3-0 lead before throwing his first pitch. And thankfully for the Sox, Miller found enough rhythm to worm his way out of further trouble in the first inning and last six innings in Boston’s 10-4 victory over the Astros at Minute Maid Park.

Miller did not have his best fastball, at least from a radar-gun-reading point of view. Instead of throwing in the mid-90s, the 6-foot-7, 210-pound left-hander was touching 88-89 mph for the most part.

But Miller was able to mix in his changeup and curveball to good effect, especially in getting Jason Michaels to bounce into an inning-ending double play in the first inning. That was one of three double plays turned by the Sox behind Miller.

Though Miller, who survived a bouncer off the back of his left shoulder in the fifth, gave up seven hits, only one other hit hurt him, a solo homer to left by Hunter Pence in the sixth.

The Sox offense, meanwhile, provided him with three quick runs in the first on an RBI single by Adrian Gonzalez, a bases-loaded walk to David Ortiz and a double-play grounder. Dustin Pedroia’s RBI double in the fifth, Yamaico Navarro’s pinch-hit homer in the seventh, Jarrod Saltalamacchia’s sacrifice fly in the eighth, Darnell McDonald’s three-run bomb in the eighth and Kevin Youkilis’ run-scoring single in the ninth gave the bullpen more than enough breathing room.

Miller’s record improved to 2-0 in three starts since being called up from Pawtucket.

It was the Red Sox’ third win in a row, boosting Boston to 4-4 on the road trip with one game remaining and to 9-8 overall in interleague play. The Red Sox had lost their last three series, but have won the series here in Houston and have a chance for the sweep Sunday.

LETTING OFF STEAM: Frustration got the better of the Sox’ David Ortiz in the third inning.

Ortiz grounded weakly to the right side, ending the inning. After his slow trot to first base, Ortiz grabbed his helmet with both hands, took it off his head and slammed it down on the dirt before handing it to first-base coach Ron Johnson.

The groundout stretched Ortiz’ hitless streak on the road trip to 0 for 9, though he had worked a bases-loaded walk in the first inning. He flied out to shallow left in the sixth, dropping him to 0 for 10 on the trip.

And that means he is now in an 0-for-20 slump. Ortiz hasn’t had a hit since June 20. He got two hits in that 14-5 win against San Diego, but whiffed his final two times up in that game and has been hitless since. His average has dipped from .326 to .302.

FINDING A SPARK? Manager Terry Francona decided to start struggling Darnell McDonald in left field over hot-hitting Josh Reddick Saturday night.

Part of the reason was that Houston starter J.A. Happ was a left-hander. McDonald is a right-handed hitter and Reddick is a lefty. There was another reason Francona opted for McDonald, who was batting an embarrassing .115.

“I really do want Mac to face a lefty because of what he can do. I want to get him going a little bit,” said Francona, alluding to McDonald’s solid season off the bench a year ago when he hit .270 with 9 homers and 34 RBI.

McDonald is one of the Sox’ few right-handed hitting options off the bench now that Mike Cameron has been designated for assignment.

McDonald’s struggles continued in his first three at-bats -- two flyouts and a double-play grounder.

But in the eighth, McDonald absolutely crushed a 2-and-0 pitch from left-hander Fernando Abad for a three-run rocket high and deep to left that put the game away, giving the Sox a 9-3 cushion. It was McDonald’s second homer of the year. The 1-for-4 effort raised his average to .125 (7 for 56).

Reddick got in the game as a defensive replacement, and went 1 for 2, raising his average to .452 (19 for 42).

NO DAMAGE: The Red Sox did not get hurt by having two players playing out of position for the first five innings.

First baseman Adrian Gonzalez was not required to make a catch in right, though he did cleanly field a single hit his way and threw a strike to the cutoff man. And designated hitter David Ortiz did not have a ground ball hit to him.

With a 4-1 lead heading into the bottom of the sixth, Francona decided to shore up his defense and not tempt fate. He took out Ortiz, brought in Gonzalez to play first, shifted McDonald from left field to right field and inserted Josh Reddick in left field.

SUCCESSFUL IN A PINCH: Yamaico Navarro, called on to pinch hit for Andrew Miller in the seventh, launched his first career homer, a shot to left on a 3-and-1 pitch. Navarro had been promoted from Pawtucket on Thursday when the Sox designated Mike Cameron for assignment.

It was Navarro’s first at-bat. He went 6 for 42 (.143) for Boston in 20 games last year.

It was the Sox’ second pinch-hit homer of the season. David Ortiz clubbed the first one, on May 29 in Detroit. The last member of the Sox to hit his first homer as a pinch hitter was Juan Diaz on June 23, 2002.