BOSTON —  How lopsided was Saturday’s Red Sox victory? Both teams finished the game with position players on the mound.

The Sox bludgeoned the visiting Chicago Cubs 17-0 in the second of three games at Fenway Park, pairing their strongest offensive output of the season with a bullpen-game shutout.

Tyler O’Neill and Ceddanne Rafaela both homered and doubled to lead Boston’s scoring surge, with Rafaela going 4-for-4 and driving in a career-high seven runs. Five Red Sox pitchers combined to allow no runs on five hits — including infielder Pablo Reyes, who tossed a scoreless ninth.

The Red Sox led 11-0 after seven innings, then piled on six more runs against Cubs designated hitter Matt Mervis, whose 55-mph breaking balls were in-game batting practice for Boston’s hitters. Chicago eventually lifted Mervis and inserted third baseman Patrick Wisdom, who got Wilyer Abreu to ground out to stop the bleeding.

The win snapped a two-game losing streak for the Red Sox, who improved to 15-13 on the season.

A towering two-run blast from one of baseball’s hottest sluggers opened the scoring in the bottom of the first.

O’Neill, who entered Saturday tied for third in the majors in home run and fifth in OPS, turned on a 3-0 fastball from Cubs starter Ben Brown and launched it off the left-field light tower for his ninth homer of the season. It scored Jarren Duran, who led off with a wall-ball double.

Rafaela extended the Red Sox’s lead with a fourth-inning sacrifice fly that drove in Masataka Yoshida. It was a strong return to the lineup for Yoshida, who went 4-for-5 with three runs scored in his first start since April 20.

“He’s a good player,” manager Alex Cora said of Yoshida. “He’s a good hitter. He’s our DH. … His swing looked faster, quicker. He was well-rested, so we expected that.”

O’Neill spurred another Boston rally in the fifth by bouncing a double off the Green Monster and later scoring on an infield single by Wilyer Abreu. It was Abreu’s eighth straight game with an RBI, the longest streak ever by a Red Sox rookie.

Chicago reliever Luke Little proceeded to hit Connor Wong and pinch hitter Rob Refsnyder to load the bases, and Bobby Dalbec reached on a comebacker off Little’s glove to score Abreu and make it 5-0.

That lead quickly ballooned to 8-0 thanks to Rafaela, who cleared the bases with a double into the corner off former Boston right-hander Colten Brewer. Rafaela then stole third and scored on a Duran groundout before Devers grounded out to end the six-run frame.

Rafaela continued his sizzling afternoon by blasting a two-run homer to center with two outs in the seventh, then doubled and scored against Mervis in the eighth. It was a scene-stealing performance at the plate for the 23-year-old, whom the Red Sox signed to an eight-year contract extension earlier this month.

“I’m not going to talk about numbers and all of that — we just want him to improve,” Cora said. “We know the upside, and we know what he can become, but this is the big leagues, and it takes a while. There’s a learning curve, and we have to be patient. We’ve been patient throughout since I got here with certain guys, and now they’re established big leaguers. We expect the same thing with him.”

Starter Josh Winckowski pitched three scoreless for Boston, stranding runners on first and third in the first inning and second and third in the second.

Brennan Bernardino struck out No. 9 hitter Pete Crow-Armstrong with two men on to complete a scoreless fourth inning. Rookie standout Justin Slaten followed with two perfect frames, lowering his ERA to 0.55 and earning the win. Cam Booser went 1-2-3 in the seventh and eighth, striking out three.

Boston announced a trade during the game, sending cash considerations to the Cubs for first baseman/outfielder Garrett Cooper. In a corresponding move, the Red Sox moved Triston Casas to the 60-day injured list.

Cooper’s arrival could push Casas’ replacement, Dalbec, out of the everyday lineup. Dalbec went 2-for-4 with two runs scored and three RBIs on Saturday, but one of his hits came off Mervis. He entered the day hitting .093/.152/.116 on the season.

The Red Sox and Cubs will close out their three-game series Sunday night at 7:10 p.m. Tanner Houck (3-2, 1.65 ERA) is scheduled to start for Boston opposite Chicago’s Jordan Wicks (1-2, 4.70).