Mike Yastrzemski, Heliot Ramos and Brett Wisely -- the bottom three batters in the order -- combined for five hits and six RBIs on Monday afternoon and the San Francisco Giants took advantage of some shoddy defense on the part of the visiting Philadelphia Phillies for an 8-4 victory in the opener of a three-game series.

Four relievers combined for five shutout innings, allowing the Giants to begin a six-game homestand with a win after having been swept in a four-game set in Philadelphia earlier this month.

Kyle Schwarber had a two-run home run, his 10th, for the Phillies, who lost for the third time in four outings on a six-game Western swing.

Staked to a 3-0 lead, Blake Snell saw it slip away thanks to Schwarber's homer in the third inning and a two-run fourth triggered by Edmundo Sosa's triple.

Seeking his first win as a Giant, the reigning National League Cy Young Award winner was pulled after four innings, having allowed four runs (three earned) and five hits. He walked two and struck out seven.

The Phillies never scored again, however, against Giants relievers Randy Rodriguez (1-0), Erik Miller, Ryan Walker and Camilo Doval. Rodriguez got credit for his first major league win after throwing a hitless fifth and sixth innings.

Meanwhile, the Giants rallied to take a 5-4 lead in the fifth on a run-scoring error by Phillies third baseman Alec Bohm and a sacrifice fly by Patrick Bailey. San Francisco tacked on one in the sixth and two more in the seventh.

Wisely's second RBI hit of the game, a double, scored Yastrzemski to make it 6-4 in the sixth. Bohm and second baseman Whit Merrifield committed errors to set the stage for Ramos' two-out, two-run single that broke the game open in the seventh.

The Phillies made three errors in the game, leading to three unearned runs. One came at the expense of starter Taijuan Walker (3-1), who was charged with six runs (five earned) in six innings. He allowed nine hits and two walks while striking out four.

Yastrzemski finished 1-for-3 with two runs and two RBIs. Ramos and Wisely each went 2-for-4 with two RBIs, highlighting a 12-hit attack that produced a ninth win in the team's past 11 games.

Bailey, Luis Matos and Thairo Estrada also had two hits for the Giants, and Matt Chapman scored twice.

Schwarber and Johan Rojas had two hits apiece for the Phillies.