Wilmer Flores, Mike Yastrzemski and Mauricio Dubon homered, and Logan Webb scattered six hits over six shutout innings to lead the visiting San Francisco Giants past the Cincinnati Reds, 6-3, Monday night in the opener of a four-game series.

Webb (3-3) fanned four, walked one and escaped a bases-loaded jam in the second inning. He threw just 86 pitches and induced two ground-ball double plays in an efficient night of work.

Meanwhile, Reds starter Sonny Gray (0-3) remains winless in six starts. The right-hander struggled from the start, yielding five hits, four runs -- three earned -- over five innings, striking out a season-low three and walking two. He surrendered homers to Flores and Yastrzemski.

Flores drilled a line drive to the first row of seats in right in the fourth inning, his third long ball of the year, for a 3-0 lead. Yastrzemski connected on a Gray fastball in the fifth for a 430-foot home run to right-center and a 4-0 Giants lead.

With Gray out of the game, Dubon continued the power display for San Francisco against reliever Carson Fulmer when he drilled a knee-high fastball 411 feet to deep left-center for a 5-0 lead.

The Reds got on the board when their top run producer, Jesse Winker, singled to left-center off reliever Jarlin Garcia with two outs in the seventh, scoring Tyler Stephenson.

The Giants added insurance in the eighth off reliever Cionel Perez, duping the Reds into a pickoff rundown of Austin Slater with two outs, allowing Darin Ruf to score from third to make it 6-1.

Tyler Naquin and Eugenio Suarez ignited Cincinnati's hopes of another rally from 6-1 down in the eighth for the second straight game by hitting back-to-back solo homers off Matt Wisler. The Reds came from behind by the same score to beat the Colorado Rockies on Sunday.

But San Francisco's Tyler Rogers made his major league-leading 24th appearance of the year and recorded his fifth save of the season by pitching a scoreless ninth.

The Giants' power display came without the services of Brandon Belt, who missed his second straight game with left side tightness. Cincinnati's injury-prone Nick Senzel appeared to hurt himself diving for a grounder in the eighth inning and tweaked the injury catching a pop-up for the final out of the ninth.

The Giants improved their National League-best record to 25-16.

--Field Level Media