SAN FRANCISCO -- Hayden Birdsong had a tough act to follow after watching Blake Snell rack up a career-high 15 strikeouts over six shutout innings in Game 1 of Saturday night’s doubleheader against the Rockies.

The 22-year-old rookie wasn’t quite as dominant in Game 2, but he still turned in another impressive performance, striking out eight over five scoreless innings to lead San Francisco to a 5-0 win and sweep both ends of the scheduled twin bill at Oracle Park.

Birdsong limited the Rockies to three hits while generating 20 swinging strikes in the 106-pitch effort. Like Snell, Birdsong leaned primarily on his fastball (36%) and curveball (29%) to overpower Colorado’s lineup and improve to 3-0 with a 2.97 ERA over six starts this year.

“They struggled, obviously, against Blake,” Birdsong said. “I’m not left-handed, I’m not Blake Snell, but I still have a curveball. That’s what they’ve struggled with in the last couple of outings we’ve had against them. They showed it again, that they keep struggling with it. Just throw strikes like Blake and try to get zeros.”

Sean Hjelle, Taylor Rogers, Erik Miller and Spencer Bivens combined to throw four scoreless innings to complete the Giants’ fifth shutout victory of the year and first since May 28 against the Phillies. San Francisco’s pitching racked up a combined 30 strikeouts on Saturday, the most in a doubleheader in Giants history since at least 1901.

After winning three straight against the cellar-dwelling Rockies, the Giants (52-55) now stand three games below .500 and 4 1/2 games out of the final National League Wild Card spot with three days to go until Tuesday’s 3 p.m. PT Trade Deadline. Manager Bob Melvin said he hopes the recent pitching performances from Snell, Birdsong and Robbie Ray will help convince the front office to keep the roster together and try to make a playoff push down the stretch.

“We’ve been kind of waiting for this whole starting pitching thing for a while,” Melvin said. “We put ourselves in a hole, but hopefully we can take a little something from these first three games and have a good game tomorrow and an off-day. Then we’re looking at Robbie again and hopefully Alex [Cobb] soon after that. It’s a pretty good starting rotation when you look at it. It’s a little bit late, but still, we have our hopes of doing well here coming up.”

“Everybody was super happy that obviously we got two wins today and won yesterday and kind of put a statement out there that we’re here to win,” Birdsong said. “We’re not just playing.”

Birdsong benefited from early run support on Saturday, as Jorge Soler led off the bottom of the first inning with a single off Rockies right-hander Tanner Gordon and scored on Mike Yastrzemski’s RBI triple to right field.

The Giants extended their lead to 2-0 behind back-to-back doubles from Matt Chapman and Brett Wisely in the second and then tacked on two more runs in the fifth via Yastrzemski’s sacrifice fly and Heliot Ramos’ RBI single. Yastrzemski is now batting .375 (18-for-48) with eight extra-base hits and seven RBIs over his last 14 games.

Rookie shortstop Tyler Fitzgerald also stayed hot, launching a solo shot off John Curtiss in the eighth to collect his eighth homer in his last 10 games. He’s the first Giant to accomplish the feat since Barry Bonds in 2004.