Bumgarner (0-4) came off the injured list to make his first start in nearly a month after recovering from a mid-back strain. The left-hander allowed two earned runs on three hits in four innings, striking out two and walking a pair in his first-ever appearance against his former team.

Bumgarner spent his first 11 seasons with the Giants, winning three championships and the 2014 World Series MVP. His 119 wins are third-most in San Francisco history and his 1,794 strikeouts rank second. He signed an $85 million, five-year contract with the Diamondbacks during the offseason.

Giants starter Trevor Cahill, who pitched for Arizona from 2012-14, only lasted 2 2/3 innings, giving up one earned run on two hits and two walks. The right-hander exited his last start with left hip discomfort, but his MRI the following morning came back clean.

Longoria and Ruf connected for the Giants’ first set of consecutive homers this year. Joey Bart and Mauricio Dubón added consecutive RBI triples in the sixth to give San Francisco a 4-1 lead.

Daulton Varsho hit his first career home run, sending a drive into McCovey Cove in the seventh to bring the Diamondbacks within 4-2. Arizona climbed within one in the eighth when Eduardo Escobar singled home Ketel Marte, but Sam Selman struck out Josh Rojas to strand two runners in the eighth.