After a rare thunderstorm hit the Bay Area on Sunday morning, the A’s offense brought some heavy thunder to Oracle Park.

The A’s skipped their heart-pounding theatrics that became the norm in the late innings over the previous two days and cruised to a 15-3 victory over the Giants, securing a three-game sweep of the season’s first Bay Bridge Series and pushing their record to a Major League-best 16-6. The win was Oakland’s 13th in its last 15 games, keeping the A’s atop the American League West standings by 4 1/2 games over second-place Houston.

• Box score

“For a while it was just doing enough and winning close games with the pitching kind of ruling the day,” A’s manager Bob Melvin said. “Now it seems that the bats have woken up some, too. When you’re playing good, you've got to get greedy and win as many as you can.”

A warm game-time temperature of 79 degrees combined with mugginess in the air from the earlier storm seemed to transform the usually pitcher-friendly Oracle Park into a hitter’s paradise. Sunday’s season-high run output, which was also the highest run total by the A’s in a road game vs. San Francisco in franchise history, saw 10 A’s hitters score at least one run. Featured in the blowout was a nine-run fifth inning -- highlighted by three home runs -- to put the A’s comfortably ahead.

Chad Pinder and Stephen Piscotty each appeared to take aim at the giant Coca-Cola bottle situated above Oracle Park’s left-field bleachers with their mammoth homers in the fifth. Pinder’s was a two-run shot off Wandy Peralta, clobbered 112.1 mph off the bat and traveling a projected 422 feet per Statcast, which qualifies as the hardest-hit homer of his career. Not to be outdone, Piscotty followed later in the inning with a three-run shot off Dereck Rodríguez that registered as the longest and hardest-hit homer of his career, traveling 454 feet to the top of the bleachers in left-center and smoked 111.1 mph off the bat.

“I have not seen a ball go that far here. That one almost hit the concourse,” Melvin said of Piscotty’s blast. “Not even in batting practice have I seen a ball go up there. It looked like it was headed for the glove. It was impressive.”

Piscotty, who was the hero of Friday night’s thrilling comeback win with a game-tying ninth-inning grand slam, added a two-run double in the sixth on Sunday to finish with a five-RBI day. Coming off a 2019 campaign that was riddled by injuries, Piscotty now has three home runs and 12 RBIs over his last nine games.

“You go back two years ago, he was arguably our best player down the stretch,” Pinder said. “He battled the injury bug last year. Stephen is one of the favorites in our clubhouse. When he’s going great, he’s somebody you want in the middle of that lineup because he seems to come up with clutch hit after clutch hit.”

Entering the game as a pinch-hitter in the fifth, Pinder nearly hit for the cycle, finishing 3-for-4 with a homer, double and two RBIs. He only entered the game as a counter-move by Melvin after the Giants went to the left-handed Peralta with one out in the fifth. Pinder did not waste any time, unloading on a first-pitch fastball for the homer.

“That was the biggest blow of the game,” Melvin said. “Good approach as a pinch-hitter. If you get an early count fastball, let it go. I think he knew exactly what he wanted to get and got it.”

Mike Fiers had to sit on the bench for nearly 30 minutes during the fifth-inning barrage of runs, though he did not allow the long rest to throw off his groove. Fiers held the Giants to two runs on seven hits and struck out four batters in six innings.

“It was a great inning for us. Almost too long,” Fiers said. “But I can’t complain as long as we’re scoring. I just had to find a way to get ready for once the inning ended.”

The lopsided score allowed Melvin a chance to get James Kaprielian in a game for his Major League debut. Kaprielian, Oakland’s No. 13 prospect who was called up just before Sunday’s game, relieved Fiers in the seventh. Though Brandon Crawford welcomed the right-hander to the big leagues with a leadoff homer, Kaprielian bounced back by retiring the final six batters he faced, finishing with one run allowed on one hit over two innings with one strikeout.

“He looks fully healthy now,” Melvin said. “He had a tough road for a while where he couldn’t get all the way healthy. Finally makes it to the big leagues and is throwing hard. It’s great to finally get him here.”

The 16th overall pick by the Yankees in the 2015 Draft, Kaprielian had a long battle with injuries upon his arrival to Oakland in the deal that sent Sonny Gray to New York at the '17 Trade Deadline. A clear sign that he’s back to full strength was apparent on Sunday as his fastball sat between 96-97 mph after it was around 91-93 mph in the Minor Leagues for most of '19.

“I’m pretty glad it’s just behind me now. It’s been a long time coming,” Kaprielian said. “There’s been a lot of ups and downs along the road to get here. I’m happy to be a part of this team. This is something I really wanted to be a part of, help these guys any way I can.”