SAN FRANCISCO -- Jake Peavy was so unprepared for his at-bat in the fourth inning Wednesday night, he barely had time to put his helmet on before heading to the plate.

Batting gloves? The San Francisco Giants pitcher had no choice but to discard them.

Apparently he should consider doing that more often.

Peavy became the fifth Giants pitcher to hit a home run this season, contributing a solo shot to a 12-hit attack that produced a 5-3 victory over the Cincinnati Reds.

Shortstop Ehire Adrianza drove in a pair of runs with a double and a triple as the Giants (77-69) matched a win by the Los Angeles Dodgers (84-61) to remain 7 1/2 games behind in the race for the National League West title.

"We're trying to win 'em all," Peavy said of the uphill battle in the division race. "We understand the situation we're in."

By winning two of three from Cincinnati in the home series, the Giants completed a 5-1 dominance of the Reds this season.

This one did not come easy, even after Peavy's home run, his first this season and the third of his career, gave the Giants a 4-0 lead in the fourth inning.

"I still feel strong," the 34-year-old assured. "My bat speed has slowed down. But at the end of the day, I know what I'm capable of."

Peavy's blast to left field was the ninth homer by five different Giants pitchers this season. The other 29 teams in major league baseball have combined to hit just 15 home runs.

No team has ever had more than five pitchers hit homers in the same season.

"Chris Heston hated to see that," Peavy said with a chuckle, referring to one of the few Giants starting pitchers without a home run this season. "It puts the pressure on him."

Peavy (7-6) also excelled on the mound, limiting the Reds to two runs on seven hits in six innings. He struck out a season-best-tying eight and did not walk a batter in running his September record to 3-0 and his lifetime mark against Cincinnati to 7-0.

Adrianza's triple came in the seventh inning and scored second baseman Kelby Tomlinson to put the Giants up 5-2 and provide a critical insurance run.

The San Francisco bullpen then held on from there, with right-hander Hunter Strickland escaping a bases-loaded, none-out situation in the eighth by allowing just one run, retaining a 5-3 advantage.

Closer Santiago Casilla then survived a shaky ninth inning in which he loaded the bases to record his 34th save.

"Again, guys really picked us up," Giants manager Bruce Bochy said of his bullpen. "Strick saved us ... and Casilla found a way to get that last out."

Reds manager Bryan Price applauded his team's comeback effort.

"They had to make some pitches, and they did," he said. "They got a big double play that kind of got things quieted down there in the eighth when they brought in Strickland."

Right fielder Marlon Byrd matched Adrianza with a double and a triple in the win. Tomlinson and left fielder Alejandro De Aza also had two hits apiece for the Giants, who have won five of six on their current nine-game homestand.

The win was San Francisco's eighth in its last 11 games overall and 26th in its last 35 at home.

Left fielder Skip Schumaker had three hits for the Reds, including one of their five doubles.

Second baseman Brandon Phillips laced a pair of doubles, center fielder Jason Bourgeois had a triple and a single, and first baseman Joey Votto also collected two hits, one being a double, in the Reds' 10-hit offense.

The Giants scored single runs in each of the first four innings, the first three coming against Reds starter Michael Lorenzen (4-9), who was pulled after allowing six hits in three innings. He walked one and struck out one.

Lorenzen was told before the game that this probably was his last start.

"I'm probably going to go to the bullpen now," he noted. "I haven't really thought about my last start this year or anything like that. It's just bullpen time."

Three of the six hits off Lorenzen went for extra bases. Adrianza doubled to drive in Byrd, who also had doubled, in the second inning, while Byrd's triple plated first baseman Brandon Belt in the third.

Catcher Buster Posey opened the scoring with an RBI single in the first inning.

Peavy's home run, his first since July 25, 2006, came off Reds reliever Collin Balester.

NOTES: Giants RHP Jake Peavy had gone 250 at-bats since his previous home run before launching his shot Wednesday. ... The other Giants pitchers to hit homers this season are LHP Madison Bumgarner (five), RHP Tim Hudson (one), RHP Mike Leake (one) and RHP Ryan Vogelsong (one). ... Four of the homers have come in the last 13 games. ... Giants 2B Joe Panik's season is over. He was transferred from the 21-day to the 60-day disabled list before the game, assuring he will not play again in 2015. He missed 41 of the last 43 games with inflammation in his lower back. ... The Giants added OF Mac Williamson and C Trevor Brown to the 40-man roster and promoted both from Triple-A Sacramento. At the same time, they designated minor-leaguer OF Daniel Carbonell for assignment. ... Reds manager Bryan Price has announced changes in his starting rotation, effective immediately. He replaced RHP Keyvius Sampson and RHP Raisel Iglesias with LHP Brandon Finnegan and RHP Josh Smith.