SAN FRANCISCO -- Close game or blowout, it makes no difference.

The Cincinnati Reds own the San Francisco Giants.

Zack Cozart's second double of the game scored Scooter Gennett with the tiebreaking run in the eighth inning Thursday night as the Reds continued their dominance over the Giants with a 3-2 victory in the opener of a four-game series.

Right-hander Bronson Arroyo combined with three relievers to scatter 11 hits for the Reds, who recorded 13-3, 14-2 and 4-0 wins over the Giants last weekend in a historically lopsided three-game sweep.

"I can't put it into words. Nice win," Reds manager Bryan Price said. "For whatever reason, when we play here, they are low-scoring, close ballgames."

A late-game substitution at second base, Gennett led off the eighth against right-hander Hunter Strickland (0-1) with a triple to the fence in center field that tipped off the glove of Giants center fielder Denard Span.

Strickland got Billy Hamilton on a grounder to first baseman Brandon Belt, holding Gennett at third, before Cozart laced a difference-making double to left-center.

"Honestly, I feel like the team in general, we're coming through in situations like that," Cozart said, trying to deflect the credit. "There are no 'me' guys here. It's a good group of guys, all pulling for one another. Everyone's happy for each other no matter who comes through.

"You're winning in a different fashion night in and night out. It's been fun."

Left-hander Wandy Peralta (2-0), the third Reds pitcher, held the Giants scoreless in the eighth before closer Raisel Iglesias stranded the potential tying run at third base in the ninth for his seventh save.

"He's pitching as well out there as any guy I've ever played with," Arroyo said of Peralta, whose ERA dipped to 1.20 after 1 1/3 scoreless innings. "Righty, lefty ... I'll take him in any situation right now."

Hamilton and Cozart had two hits apiece, and Joey Votto had two RBIs for the Reds, who won for the sixth time in their past seven games.

The Reds were opening a seven-game trip.

Belt hit a solo home run in the first inning and Span added one in the fifth, both off Arroyo, to provide all the San Francisco scoring.

Playing for the first time since missing 17 games with a sprained shoulder, Span collected four hits for the Giants, who were opening a seven-game homestand after a 2-7 trip.

Neither starting pitcher got a decision.

Arroyo allowed the two home runs but only four other hits in his six innings. He struck out three and walked one.

Coming off a disastrous start in Cincinnati on Saturday in which he was torched for 11 hits and 10 runs (eight earned) in three innings, Giants left-hander Ty Blach worked seven effective innings, allowing just two runs on five hits. He struck out two and walked one.

"I was definitely fired up," Blach said. "I wanted to prove you can get those guys out and you can bounce back."

Giants manager Bruce Bochy took no solace in losing a close game after the three one-sided affairs in Cincinnati, but he did take time to praise Blach.

"It was great to see," he said. "He did a great job bouncing back from last outing against these guys. I was proud of him. It's a shame we couldn't give him a win."

NOTES: The Reds have won 40 of 64 games against the Giants over the last 10 seasons, a .625 winning percentage that is the highest among all San Francisco opponents over that stretch. ... The Giants activated SS Brandon Crawford (strained right groin) and CF Denard Span (sprained shoulder) from the disabled list before the game. To make room on the roster, RHP Reyes Moronta was demoted to Double-A Richmond, and INF Conor Gillaspie (back spasms) was placed on the 10-day DL. ... The Reds promoted RHP Lisalverto Bonilla from Triple-A Louisville before the game and have slotted him to start Saturday in place of RHP Rookie Davis, who was sent to Triple-A Louisville on Wednesday. ... During the break between the top and bottom of the second inning, Giants fans sang "Happy Birthday" to Willie Mays, who turned 86 on Saturday while the team was on the road. Mays attended the Thursday game.