The Astros (51-72) went 1 for their first 12 with runners in scoring position Friday night until Marisnick's 10th inning, two-out double drove in two runs, helping Houston claim a 5-3 victory and end its eight-game losing streak in Boston.
The win also matched the Astros' 2013 total.
"It's a huge credit to the players in that locker room and our staff," manager Bo Porter said. "They worked extremely hard and we still have six weeks left to go in the season."
Marisnick, acquired from Miami at the trade deadline, is 14 for 31 over his last eight games after going 11 for 71 over his previous 20 contests.
Peacock (3-8, 5.25 ERA) hopes his third career matchup with Boston (55-66) will turn out better after struggling in the previous two encounters.
He recorded only one out in an 11-0 home loss to the Red Sox on July 13, allowing Brock Holt's leadoff homer, another hit and a walk before being yanked by Porter. Peacock also surrendered five runs, six hits and five walks in 3 1-3 innings of an 8-4 defeat in Boston on April 27, 2013.
More recently, Peacock gave up 15 runs over 8 2-3 innings in back-to-back road losses to Oakland and Philadelphia before putting together a better showing Monday versus Minnesota. The right-hander yielded two runs - one earned - in five innings, but didn't receive a decision in a 4-2 defeat.
Though Friday's loss snapped the Red Sox's winning streak at four games, they continue to enjoy the recent power surge by Yoenis Cespedes. Cespedes hit his third home run in five games and 20th this season in the fourth inning off Dallas Keuchel. Prior to this stretch, Cespedes had hit only three in his previous 39 games.
The third-year outfielder will look for more success against Peacock after taking him deep twice in four at-bats earlier this year.
Rubby De La Rosa (4-4, 3.21) gets the nod for Boston after limiting his last two opponents to two runs over 13 innings. He matched a career high with eight strikeouts while making it through seven in a 3-1 road victory over the Los Angeles Angels on Sunday, and will be looking to record a fourth straight quality start for the first time in his career.
"He is pitching with a lot of confidence and maintaining his stuff deep into games," manager John Farrell told MLB's official website.
De La Rosa struggled in his only previous start against Houston, allowing five runs over 4 2-3 innings in a 7-0 loss for the Los Angeles Dodgers on June 18, 2011. He pitched a scoreless inning of relief in Houston on Aug. 6, 2013, for the Red Sox.