SAN FRANCISCO -- Don Mattingly doesn’t need data to know that Jorge Alfaro’s power is legitimate.

Alfaro launched a two-run homer in Saturday’s seventh inning to break a scoreless tie and put the Miami Marlins on course for a 4-2 victory over the San Francisco Giants.

Alfaro’s clout off Giants ace Madison Bumgarner traveled a projected 473 feet, making it the second-longest homer hit at Oracle Park since Statcast began tracking home run information in 2015.

• Box score

That failed to impress Mattingly, who reached or exceeded 30 home runs three times during an illustrious 14-year career. Like many other observers, Mattingly casts some doubt upon the prodigious power displayed throughout the Major Leagues.

Told of the projected 473-foot distance of Alfaro’s clout, Mattingly said, “This year you can’t really count any of that. When you go to different ballparks, during batting practice, you see balls go to places they never went before. Almost every club is setting franchise records in home runs. Obviously something is going on.”

But the force of Alfaro’s drive moved Mattingly nonetheless.

“That ball was hit, though,” Mattingly said. “Georgie’s got tremendous power. I wouldn’t quite put him in [Giancarlo] Stanton’s category, but he’s in that [Marcell] Ozuna category where, when he hits them, they go. Right field. Center field. Left field. This kid’s got tremendous power. I don’t want to discount that.”

Alfaro’s 15th homer of the season also elicited praise from the man who surrendered it. Bumgarner threw Alfaro an 0-1 curveball that Miami’s catcher golfed more than halfway up the left-field seats with Starlin Castro aboard.

"He did a really good job,” Bumgarner said. “That was a pretty good spot, I thought, to throw it. He just hit it. Obviously, looking back, I should have done something different, but I like the pitch, I like the location right there. That pitch in that spot gets a lot of swings and misses for me, and ground balls, too. Unfortunately, not in that case."

In fact, Alfaro was anticipating a fastball from Bumgarner. But Alfaro managed to adjust: “I saw [the ball] out of his hand and just waited for it.”

Alfaro may have been helped by advice that he and other Marlins received from shortstop Miguel Rojas.

“Against that curveball, you have to kind of swing under the ball, so you don’t keep hitting it on the ground,” Rojas said.

Alfaro’s homer ended Miami’s 20-inning scoreless streak, unleashing momentum that continued after the Giants pulled even in their half of the seventh on Donovan Solano’s pinch-hit, two-run triple. Miami added another pair of runs in the eighth. Rojas sent home pinch-runner Magneuris Sierra with a two-out double, then scored on Lewis Brinson’s single.

Marlins right-hander Robert Dugger, who began the season in Double-A, continued his progress by working 6 1/3 innings in his fifth Major League start. He yielded two runs and five hits.