SAN FRANCISCO -- As Kyle Harrison prepared to make his Major League home debut, there was no telling how the extra adrenaline was going to affect him. This was, after all, a very big deal for him. He was taking the mound at the very ballpark that helped shape his earliest baseball fandom, 30 miles away from the city where he grew up.

It took only a few minutes to find out how Harrison, a product of Concord, Calif., would harness this extra wave of emotion. In only his second big league start, the 22-year-old lefty was in control from the beginning, striking out 11 batters over 6 1/3 innings in a 4-1 Giants win over the Reds. This was one San Francisco sorely needed, after slogging through an arduous, mostly unsuccessful August.

“It was about as an electric performance by a pitcher as we've seen since I've been here in San Francisco, right up there with any pitching performance,” manager Gabe Kapler said.

The win kept the Giants relevant in the National League Wild Card race, where they’re a half-game behind Arizona for the final spot. They kept the Reds 1 1/2 games back in the chase, and the Giants also won round one in a three-game tiebreaker showdown, should the postseason race come down to that. With head-to-head records determining tiebreakers in the standings, whoever wins this series will have that edge.

While the Giants took care of business on the field, there was plenty of activity in the stands, too, in the form of a Harrison cheering section that was loud and expansive, popping up in a multitude of spots at Oracle Park.

They were everywhere. A dozen-plus were packed into a suite on the club level; another 20 or so were crammed in a section in the lower bowl, several rows behind the Giants dugout.

And then there were Harrison’s parents, Kim and Chris, who, rightfully, had the best seats of all members of the Harrison Cheering Section -- dugout club, eye level to the field, feet from the Giants dugout.

Harrison, for his part, said he was oblivious to all of it.

“I didn't see them at all,” he said. “I was dialed in. I think my buddies were saying they were somewhere close, but I was locked in. I didn't see them at all.”

Regardless, Harrison provided them with an eyeful as he hit multiple club milestones, making this start not only exhilarating, but historic, too.

Consistently touching 95 mph with his fastball, Harrison struck out the first five batters he faced. By the end of the third, he had fanned seven, becoming the youngest Giants pitcher in the last 50 seasons (since 1974) to have seven strikeouts through the game’s first three innings. That includes the Giants' eight postseasons over this stretch of time.

Harrison hit another historical marker in the sixth, when he fanned Noelvi Marte -- his 11th strikeout. That made Harrison the youngest Giants pitcher to record 11 strikeouts since Madison Bumgarner did so on June 26, 2011. Harrison, at 22 years, 16 days, narrowly missed topping Bumgarner, who was a mere 21 years and 329 days old when he struck out 11.

“The funny part is I think everybody's kind of shocked, like, ‘Oh man, wow, this is incredible,” said catcher Patrick Bailey, who played alongside Harrison during their ascent through the Giants’ Minor League system. “I’ve been seeing this for three years and have been part of it for three years. It’s been really cool to just see him do it on the biggest stage in front of a really good crowd.”

Harrison was on a loose pitch limit, somewhere around 80 to 85 pitches. He finished the sixth with 78, which seemed like an apropos time for Kapler to hand the game over to the bullpen.

But then he let Harrison go back out for the seventh.

“It felt like this was a historic performance at that point, and one that warranted an additional up, even though it wasn't totally comfortable,” Kapler said. "He was that good and that deserving.”

When he did head to the mound to lift Harrison later that inning, Kapler took his time getting there, and he waited a little longer once he arrived. This gave Harrison an extra moment to breathe it all in, and enjoy the ovation that followed him back to the dugout.

“Sometimes you forget to get lost in that moment,” Kapler said. “And there's just so much adrenaline and so much excitement and your family’s out there that you just don't necessarily pause and feel that ovation. So just maybe a little bit of a nudge in that direction.”

“It was pretty cool for Kap to say, ‘Take this moment in,’” Harrison said. “And so I did. And it was awesome.”