HOUSTON -- When Khris Davis mashed a two-run blast over Minute Maid Park's train tracks in the second inning of Tuesday's 21-7 blowout of the Astros, he cemented Oakland's place among some of the most prolific home run-hitting clubs in the history of baseball.

The home run was Davis' 20th of the season, joining Matt Chapman, Matt Olson, Marcus Semien, Jurickson Profar, Ramón Laureano and Mark Canha as the seventh A's batter to reach the 20-homer mark. Entering the season, there had been only seven clubs in MLB history with seven 20-homer guys in a season. The Dodgers accomplished the rare feat in 2018.

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It's fitting that Davis, MLB's reigning home run champion, who entered the year with more homers than any player since the start of the 2016 season, was the one to cap off the historic accomplishment. But in a season where the power numbers are uncharacteristically down for the A's slugger, Tuesday's home run -- in a win that helped the A's protect their Wild Card lead -- might be the spark needed to get him going.

"Almost had another one too," A's manager Bob Melvin said of Davis, who was robbed of a second homer on a leaping catch by Josh Reddick in the fourth. "He seems to be swinging the bat a little bit better than he has. Not just the homers, he's getting some hits and hitting the ball the other way. He's feeling better about himself. This is a guy that can really help us, as he has in the past. We're hoping he heats up some."

Since June 19, Davis had three homers over 57 games before Tuesday. He entered the night with 286 players having hit more home runs than him this season, but Davis reminded everyone of the marvels he can do with the bat.

Davis unloaded on a first-pitch changeup from Astros reliever Cy Sneed for a majestic shot, tagged 104.2 mph off the bat and sent a projected 422 feet, which registered as his longest home run since April 12, according to Statcast.

It wasn't the only historic home run of the night for Oakland. Olson, who blasted his 30th and 31st of the season, joined Jason Giambi and Mark McGwire as just the third first baseman in Oakland history to reach the 30-homer mark.

Olson and Chapman also give the A's two 30-homer hitters in a season for the first time since Frank Thomas and Nick Swisher in 2006. Olson's achievement only gets more impressive when you factor in the 35 games he missed at the start of the season.

"This is one of the premier players in the game," Melvin said of Olson. "He gets big hits, he hits home runs and plays spectacular defense. He's a cornerstone for us. The numbers are terrific right now, and there's no telling what they would look like if he had those extra six weeks."

The missed time was due to a hamate surgery on his right hand. That's typically a procedure that leaves hitters without much power in the early going, but Olson bucked that philosophy by belting seven home runs over his first 21 games back from surgery and took off ever since.

"It's cool, definitely," Olson said of the 30-homer mark. "I didn’t know what to expect because I had heard the power was something that took a while to come back. I’m happy with where I’m at coming back from the injury and just glad we’re playing winning baseball.”

The home runs were quite the contrast for the A's offense, after it plated seven runs on eight hits in the first inning, matching Oakland's season-high for hits in the first. All eight hits in Tuesday's opening frame were singles.

Speaking of contrast, seven of those eight first-inning hits came off Astros starter Wade Miley, who was chased from the game just one out into his start. It was a huge difference from the last time Miley faced the A's in Houston on July 23, when the lefty held Oakland to two runs over eight innings.

"The last time we were here, he was speeding us up and we were swinging at pitches we don't typically swing at," Olson said. "I think today we focused on not letting him speed us up. Slow it down and make him be in the zone. He wasn't as sharp as he was the last time, and we didn't help him out at all."

Melvin has lauded his club's ability to brush off a bad loss throughout the season, and Tuesday's resilience was quite extreme.

After enduring their worst defeat of the year, a 15-0 loss in Monday's series opener, the A's returned the favor in impressive fashion. They bounced back with 21 runs, 25 hits and six home runs, all season highs. The A's are only the 2nd team in the modern era to lose a game by 15 runs, then win their next game against the same opponent by 14.

Each member of the starting lineup recorded at least two hits and one RBI, with two-homer efforts from Olson and Sean Murphy. Going back to 1908, that had never happened in franchise history before.

"To be able to come back and watch what happened yesterday, we always know we can compete against these guys," Olson said. "And to do it in this fashion was nice."