Aquino maintained his dizzying home run pace, leading off the second with a drive to left field off Drew Smyly that reached the upper deck for his 15th homer of the season. He needed just 122 plate appearances to collect them, 13 fewer than the record of 135 set by Hoskins in 2017.
Hoskins responded in the third with his 26th homer, a two-out, two-run blast into the Reds' bullpen. He briefly celebrated by raising his right fist for a few steps between first and second base.
"He got on first base late in the game, and I told him: `Keep going. This is something you'll remember for the rest of your life," Hoskins said of Aquino. "It's impressive to watch. He's a big kid. He got up on me, and I was taken aback."
Hoskins in 2017 became the quickest player ever to 11 home runs, reaching the mark in 18 games. Aquino went deep 11 times in 17 games.
Harper extended his hitting and scoring streaks to 10 games with a liner into the right-field seats in the eighth inning off Wandy Peralta. Hoskins followed two pitches later with his second homer of the game.
"He looks really relaxed and confident," Phillies manager Gabe Kapler said of Hoskins, who was ejected from Saturday night's game against the Mets for arguing balls and strikes. "Obviously, he wants the calls to go in his direction. We've seen that the past few days, but he's not letting it beat him down."
After beating the Mets 5-2 on Sunday night, the Phillies have two straight wins for the first time since Aug. 20-21 at Boston. They remain 2 1/2 games behind the Cubs for the second NL wild card after Chicago beat Seattle on Monday.
Relying on his curveball, Smyly (3-6) tied his season high with eight strikeouts while earning his first win in six starts since beating San Francisco on July 30. He gave up four hits, one run and three walks in 5 1/3 innings.
"That was the key to my success," the left-hander said. "I was throwing it early for strikes and getting strike one on the hitters. I feel like getting strike one puts me in a whole other picture."
Cincinnati's Anthony DeSclafani (9-8) shook off a rough start to last seven innings, giving up three hits and four runs with two walks and eight strikeouts.
The Phillies never trailed after Kingery's shot over the center-field fence in the second, his 16th homer of the season.
"It is no secret that I have to cut down on home runs, but I got ahead of a lot of hitters today," said DeSclafani, who gave up multiple homers in a game for the seventh time this season. "It was two pitches. Basically the one to Kingery was elevated a little bit, but he had an off-balance swing that he got on the barrel of the bat and it barely got out. I guess you've got to tip your cap."
SO FAR, SO GOOD
Hoskins has five home runs and eight RBI in five career games at Great American Ball Park.
Kingery's homer gave him five RBI in two at-bats over two games. His eighth-inning, three-run double snapped a 2-2 tie against the Mets on Sunday night.
The scoreboard showed a message saying "Thank you, Jared Hughes," when the former Red took the mound in the sixth for his first appearance in Cincinnati since the Phillies claimed him off waivers on Aug. 15. "I made a lot of friends in Cincinnati and formed relationships that I'll cherish for the rest of my life," he said. "That meant a lot to me."
Phillies: In his only career start against the Reds, on July 28, 2018, RHP Vince Velasquez (6-7) allowed six hits and five walks in five innings of a 6-2 loss in Cincinnati.
Reds: The Reds announced after the game that RHP Lucas Sims (2-1) would start Tuesday's game in place of LHP Alex Wood (1-3), who developed what were described as "back issues." Wood missed most of the first four months of the season with lower back stiffness.
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