SAN FRANCISCO _ Greg Garcia began the day with a home run, his first leading off a game.
Rookie Ty France hit two of them for the first time in a major league game.
Eric Hosmer fell one short of what would have been his first career cycle.
Eric Lauer struck out a career-high nine batters and allowed a pair of two-run homers among five total hits in his six innings.
The Padres won a game 8-4 and won their third series among the 15 they have played in the second half.
The victory over the Giants at Oracle Park was one to savor on the first day of the season's final month, a warm and sunny afternoon on the San Francisco Bay before they headed to the airport for a flight to Phoenix.
There haven't been many like it of late, even though the victory did improve them to 13-12 over their past 25 games.
The team that entered Sunday with the 13th most home runs in the majors (a franchise-record 195) had hit multiple homers just once in its previous 13 games and hadn't hit three in a game since Aug. 10 (19 games).
Garcia's shot to the thin section of bleachers atop the tall right field wall came on the eighth pitch he saw from Giants starter Jeff Samardzija (9-11).
Nick Martini followed with a double, his third hit in six at-bats since the Padres claimed him off waivers from the A's on Wednesday. He scored two batters later when Hosmer lined the first of his three hits, a double, to right field to put the Padres up 2-0.
The lead didn't last long.
Donovan Solano reached below the zone to line a fastball the other way into right field leading off the bottom of the first against Lauer. After striking out Austin Slater, Lauer sent a 2-2 slider darting across the zone and inside to right-handed Kevin Pillar, who yanked it down the left field line for his team-leading 20th home run of the season and fifth against the Padres.
Two fly balls got Lauer out of the inning, and he retired 14 of the next 16 while the Padres went about building what became a five-run lead.
France launched a 424-foot missile to left field with one out in the second to put the Padres up 3-2.
His second homer punctuated a four-run sixth inning that Hosmer led off with a triple.
Hosmer scored the inning's first run when Wil Myers chopped a ball slowly down the line that third baseman Evan Longoria hurdled, thinking it would bounce foul. When it stayed fair on its path into left field the ball, Myers stood on second with a double.
Austin Allen walked, and Giants manager Bruce Bochy, who is retiring after the season and was managing his final game against his former team, walked out to replace Samardzija.
France, who began the day with two homers in 130 at-bats, sent the first pitch from Fernando Abad over the wall in right field to make it 7-2.
Lauer (8-8) had retired seven batters in a row before Slater led off the sixth with a single. Pillar followed with a fly ball to center before did Evan Longoria drilled a first-pitch fastball 411 feet and over the center field wall to make it 7-4.
After Longoria's homer, Lauer ended the sixth with strikeouts of Stephen Vogt and Aramis Garcia on foul tips.
Luis Perdomo pitched a scoreless seventh, and Andres Munoz struck out all three batters he faced in the eighth.
David Bednar pitched a perfect ninth in his major league debut.
