OAKLAND -- Giants manager Bob Melvin predicted that Grant McCray’s blazing speed would pressure opposing defenses every time he put a ball in play.

“He’s the kind of guy that hits a ground ball and is going to create a little angst for every infielder because he gets down the line so good,” Melvin said.

Even pitchers aren’t immune, as A’s right-hander Osvaldo Bido learned on Saturday night. McCray beat out an infield single to break up Bido’s no-hit bid in the sixth inning and delivered two of the Giants’ four hits in a 2-0 loss in the Bay Bridge Series opener at the Oakland Coliseum.

The Giants were no-hit by Bido until McCray reached on a swinging bunt. McCray, the club’s No. 11 prospect per MLB Pipeline, tapped a 2-1 changeup down the third-base line and then used his wheels to beat out Bido’s throw to first, giving the Giants their first hit and second baserunner of the game.

“I saw [A’s third baseman] Darell Hernaiz back up after the [1-1] pitch, so I was like, ‘I might bunt here,’” McCray said. “But a swinging bunt works just as fine. I was trying to start a rally for us.’”

McCray needed only 4.19 seconds to get from home to first and recorded an elite 30.8 ft/sec sprint speed on the play, well above the Major League average of 27 ft/sec.

“He floats," Hayden Birdsong said. “It’s effortless when he runs. When you’re fast, you’re fast.”

McCray also used his speed to rob a hit in the fourth when he charged in and made a sliding grab on Miguel Andujar’s blooper to center field. He stretched a single into a double in the eighth, securing his second consecutive multihit effort.

“As soon as I hit that, I was like, ‘Get two,’ just because [A’s center fielder JJ] Bleday is a lefty, so he’s going to have to make a spin-move throw and have to make a good throw,” McCray said. “I got in there and beat it.”

The Giants called up McCray primarily to upgrade their outfield defense and athleticism on the bases, but the 23-year-old rookie has enjoyed promising results at the plate, going 4-for-10 with a home run and two RBIs over his first three Major League games.

“He’s off to a great start,” Melvin said. “He’s playing with a lot of confidence. His speed, his defensive ability, he certainly looks the part. He’s fast and having good at-bats right now against guys he’s never faced before.”

McCray’s performance wasn’t enough to spark the Giants’ punchless offense, which mustered two other hits -- a pair of singles by Mark Canha -- en route to their fifth loss in their last six games. San Francisco (62-63) is averaging only 2.5 runs per game over that span, causing the club to slip below .500.

“Some games we have good games, some games we don’t,” Melvin said.

The Giants’ cold bats were unable to support Birdsong, who gave up one run on three hits over 4 2/3 innings. Birdsong entered Saturday having allowed 12 earned runs over 6 1/3 innings (17.05 ERA) over his previous two outings. He looked much sharper against the A’s, using his curveball to induce three of his five strikeouts.

The 22-year-old rookie blanked the A’s through his first four innings, but ran into trouble in the fifth after giving up back-to-back singles to Seth Brown and Zack Gelof and then walking Max Schuemann to load the bases with one out. Lawrence Butler put Oakland on the board with a sacrifice fly before Melvin opted to lift Birdsong in favor of Spencer Bivens, who coaxed an inning-ending groundout from Brent Rooker to limit the damage.

“It was better, let’s put it that way,” Birdsong said of his 78-pitch outing. “I’m happy I put up some zeros and gave us a chance. Obviously, I would have liked to finish the fifth and work into the sixth and maybe the seventh and help the bullpen out a little bit, but things happen and you need guys to come in.”

Brown extended Oakland’s lead to 2-0 with a two-out RBI single off Bivens in the sixth, and the Giants couldn’t erase the deficit after going 0-for-8 with runners in scoring position.

“They pitched well, but we did have some opportunities,” Melvin said. “They had a situational at-bat. They got a sac fly and a base hit. It ended up being enough. We didn’t come through in ours. That was the difference in the game.”