Three batters after Mancini's second home run, Gentry grabbed one of the rookie's Louisville Slugger C243 model bats and hit a two-run homer of his own. Not to be left out of the party, three batters later, Machado hit another two-run shot while also using one of Mancini's bats.
Baltimore manager Buck Showalter was amazed by the eighth-inning scene.
The three-homer outburst came with the Orioles holding a 6-1 lead, which put Showalter in an awkward position when it comes to the unwritten rules of baseball.
"When you're ahead like that, you're trying to be respectful of the opposition and not have too much fun," Showalter said, "but that was one, I just went, 'Really?' When the third one went and it hit the foul pole ... Are you kidding me? Come on!"
With seven home runs total between this season and a September call-up last season, Mancini has joined Trevor Story and Dino Restelli for the most home runs hit in the first 12 games of a player's career.
"It's humbling to hear that, especially with how many legends have played the game," Mancini said. "To make your mark in any way is really neat."
Despite his hot start, Mancini has played in just seven of the Orioles' 11 games due to a roster crunch. The 25-year-old has started games at both corner outfield positions, served as a designated hitter and come on as a pinch hitter, and on Sunday, he finally started a game at his natural position, first base.
There's no guarantee that Mancini will be in the lineup for the team's next game, as the Orioles will lose the DH when they travel to Cincinnati for a three-game series that starts Tuesday.
Regardless, Mancini is enjoying his moment in the sun.
"It was pretty fun and pretty cool that they both hit home runs," Mancini said. "I might need an extra shipment here soon."