SAN DIEGO -- Kyle Higashioka understands the gig. When the game is late and close, and he¡¯s due for a big at-bat, well ¡­ sometimes he doesn¡¯t get to take that big at-bat.

¡°I¡¯m no stranger to getting pinch-hit for,¡± Higashioka said with a laugh. ¡°You know, if I hit like [Fernando Tatis Jr.], I wouldn¡¯t.¡±

Indeed, for much of the season, the Padres have typically pinch-hit for Higashioka late in games. But with Tuesday¡¯s game against Oakland tied in the bottom of the ninth inning, they entrusted their ninth-hitting backup catcher with the game¡¯s decisive moment.

And did Higashioka ever deliver. He launched a walk-off solo home run into the first level of the Western Metal Supply Co. building in left field, sending the Padres to a dramatic 4-3 victory over the A¡¯s at Petco Park.

¡°He¡¯d more than earned his at-bat,¡± said Padres manager Mike Shildt, alluding to Higashioka¡¯s recent hot streak at the plate. ¡°Good for him. He¡¯s done a nice job for us in both phases. And he¡¯s got some pop.¡±

No kidding. Oakland reliever Scott Alexander hung a 2-2 changeup over the outer half of the plate. Higashioka turned on it, and sent a 103.9-mph rocket into the seats -- his first career walk-off home run and his second walk-off hit of any kind.

¡°That¡¯s kind of the last thing that was going through my mind, especially with a high ground-ball guy,¡± Higashioka said. ¡°Usually, you get too big against those guys, you end up just pounding it into the ground. We definitely just needed a baserunner. Luckily, he hung the changeup, and I just stayed through it.¡±

Added Shildt: ¡°Big moment at Petco. That was fun.¡±

Much-needed, too. The Padres had given away a lead in the eighth inning when Oakland¡¯s Tyler Soderstrom launched a game-tying, two-run homer off right-hander Enyel De Los Santos. Shildt revealed after the game that setup man Jeremiah Estrada was sick and had been sent home and thus was unavailable.

• Padres' injuries and roster moves

In the bottom of that inning, outfielder Jurickson Profar exited the game after he swung and missed at a pitch and grabbed his knee. Shildt would later say that Profar has been battling knee soreness for a while and that the injury was not overly concerning.

Still, the Padres had taken a couple of late punches in a game they¡¯d led since the fifth inning. In the ninth, Higashioka punched back.

¡°It was, overall, kind of a dicey game,¡± Higashioka said. ¡°They were having a lot of good at-bats, and they had a lot of traffic, especially early. ¡­ We were all upset about losing the lead late like that. But this team just shows so much resilience, day in, day out.¡±

Higashioka arrived as perhaps the least heralded piece in the five-player package the Padres received when they traded Juan Soto to the Yankees in December. A light-hitting, defense-first catcher, Higashioka struggled even more than usual at the plate to start the season. He entered June with a minuscule .380 OPS.

But the Padres love his work behind the plate, and he¡¯s found a niche in backstopping Matt Waldron and his dancing knuckleball. Lately, too, Higashioka has begun to hit, and he¡¯s seen an uptick in playing time as a result. In five games this month, he¡¯s hitting .353 with four home runs.

¡°He¡¯s a great person,¡± right-hander Randy V¨¢squez said through interpreter Pedro Gutierrez. ¡°On a personal note, he¡¯s been able to help me out with my gameplan, just trying to execute whatever we have planned for that particular day. And he¡¯s been a great teammate for me the last few years.¡±

V¨¢squez, who came over with Higashioka in the Soto trade, allowed a leadoff home run to Abraham Toro and plenty of baserunners after that. But he deftly navigated it and settled in to pitch five innings of one-run ball.

Tatis -- as red-hot as Higashioka alluded to -- extended his hitting streak to 17 games with a first-inning single. That¡¯s the longest active streak in the Majors and halfway to Benito Santiago¡¯s franchise record of 34 games set in 1987.

The Padres grabbed a 3-1 lead in the fifth inning, scoring three runs with four consecutive two-out hits -- on four consecutive pitches, no less. It was Profar¡¯s two-run single that put the Padres on top.

Late drama ensued before Higashioka, the unlikeliest of heroes, ended it.

¡°A huge swing for him and for us,¡± Shildt said. ¡°That¡¯s a big win. That¡¯s a nice ballgame. A good win all the way around.¡±