HOUSTON — The emphatic fist pump Houston Astros manager Bo Porter delivered at the close of the top of the eighth inning offered perspective on just how long he had waited to relish a moment of modest triumph.

The Astros’ beleaguered bullpen shined at that juncture and preserved a second consecutive stellar start from left-hander Brett Oberholtzer in a 2-0 victory over the Boston Red Sox (68-46) Monday night at Minute Maid Park.

Houston (37-74) had been rudderless since trading closer Jose Veras to the Detroit Tigers on July 29 for minor league outfielder Danry Vasquez. But with Oberholtzer (2-0) working seven scoreless innings for the second time in six days, all that was required of Wesley Wright and Josh Fields was to record six outs against baseball’s most prolific offense.

They did precisely that, but not without drama. Wright issued a leadoff walk to Jacoby Ellsbury in the eighth inning before David Ortiz added a two-out single to center field. Fields entered and struck out Mike Napoli, inspiring Porter to showcase some emotion in support of his bullpen.

“We’ve played a lot of close games and we’ve had our heartache,” Porter said. “Our bullpen has given up some leads, so I think a lot of that emotion was more so about those guys coming in the crucial situations which they were put in today and being successful.”

Fields returned in the ninth and struck out the side to record his first career save. He became just the second pitcher on the current roster to earn a save, joining left-handed starter Erik Bedard, who got one in the season opener against the Texas Rangers on March 31.

Oberholtzer became the first pitcher to work seven-plus scoreless innings in each of his first two career starts since right-hander Marty Bystrom did so for the Philadelphia Phillies against the New York Mets and the St. Louis Cardinals on Sept. 10 and Sept. 14, 1980, respectively.

He allowed four hits and two walks with two strikeouts over seven shutout innings, recording both strikeouts with Red Sox left fielder Jonny Gomes at third base representing the tying run in the seventh.

“They came at a good time,” Oberholtzer said of the strikeouts. “The lefty matchup — I had to win that with (Stephen) Drew, and I got him with a fastball away that he swung through. Then to finish the seventh, I had to dig deep and take it one pitch at a time like I said, and it worked out. It paid off.”

Houston started generating traffic against Red Sox starter John Lackey (7-9) in the second inning, advancing runners into scoring position three consecutive frames before finally breaking through in the fifth.

Lackey relied on strikeouts to elude danger in the third and fourth. He struck out the side in the fifth, but not in time to keep Houston off the scoreboard. L.J. Hoes singled and stole second base before Robbie Grossman ripped a first-pitch cutter into right field two batters later, driving home Hoes and snapping the scoreless tie.

“I thought John had really good stuff tonight,” Red Sox manager John Farrell said. “He had good secondary stuff and got a lot of key strikeouts when he needed them. Oberholtzer threw the ball over the plate. He got ahead of us a lot and when we were able to get a chance off him — which was not too often tonight — he was able to get the key outs when he needed it in a couple of spots.”

The Astros doubled their 1-0 lead in the seven th inning when Brandon Barnes delivered a squeeze bunt off right-hander Junichi Tazawa that scored Hoes from third base. Speed played a critical role in the Astros’ success, as Houston swiped a season-high six bases.

“They are real aggressive, but I like that,” Red Sox catcher Jarrod Saltalamacchia said. “I like it because it gives us the chance to do some things. They’re aggressive; they are trying to make some things happen.”

NOTES: Red Sox OF Daniel Nava was placed on paternity leave and will miss the series against the Astros. Nava was with his wife when she gave birth to their daughter Monday morning. RHP Brandon Workman, who was optioned to Triple-A Pawtucket last Wednesday, replaced Nava on the roster. Nava will return for the four-game series in Kansas City against the Royals beginning Thursday. … Grossman made his second consecutive start batting first following his 2-for-5 effort Sunday against the Minnesota Twins. Grossman was batting .213 with a .320 on-base percentage in 27 starts atop the order entering Monday.