Twelve runs marked the Phillies' highest total since a 15-13, 11-inning loss win against the Braves on May 2. It was just their fourth double-digit scoring game this season after recording 11 during last year's 102-win campaign.
"It felt like one through nine, we were doing everything," Halladay said. "We were getting extra-base hits. We were hitting home runs. Guys were getting on base. It wasn't one or two guys. ... You've seen each guy kind of chip in at times. But to have everybody kind of all at once, for me, it was one of the better offensive games we've had all year."
Each position player tallied at least one hit, with Juan Pierre and John Mayberry Jr. notching three apiece. For Mayberry, it was his third three-hit game of the season, highlighted by a two-run blast in the sixth.
Ryan Howard and Erik Kratz each homered, singled and drove in two runs. Chase Utley and Domonic Brown each chipped in doubles and two RBIs.
"You got eight [runs Sunday] and then 12 today," Kratz said. "That's putting some bats on some balls."
Those bats picked up Halladay, who did not match his recent performances. In his three previous starts, including two wins, Halladay allowed just four runs over 22 innings. On Monday, the two-time Cy Young Award winner gave up five runs on 10 hits over seven innings with three strikeouts and one walk.
Manager Charlie Manuel said he thought Halladay battled despite not having his best command.
Halladay gave up hits to the first four batters he faced, but the Reds scored only twice in the first frame after a baserunning blunder by Chris Heisey.
The Phillies halved their deficit in the bottom of the first and tied the game on a third-inning solo shot from Howard, his eighth of the season. An inning later, Kratz gave the Phillies their first lead with a solo homer. Kratz has seven homers in just 61 at-bats.
Halladay surrendered three runs on four hits in the fifth, but that marked the last time the Reds scored.
Philadelphia batted around in a four-run fifth to take a 7-5 lead. Utley doubled to drive in a run, Mayberry singled home another and Brown smoked a tiebreaking two-run double down the right-field line to chase Cincinnati starter Mike Leake.
The seven earned runs Leake gave up tied a career high. The right-hander threw some good pitches, Kratz said, but the Phils were patient and didn't chase pitches on the corners. When they got their pitches, they didn't miss. Collectively, they were able to raise his pitch count quickly.
"It's always kind of ironic, I think," said Halladay, who won for just the 10th time in his illustrious career when allowing at least five earned runs. "Just when you think you're not catching a break, all of a sudden, we come out and put up a bunch of runs. It's nice, a good feeling."
"They've got a different lineup than they had earlier in the season," Reds manager Dusty Baker said of the Phillies. "They've got their boys back, and the guys they got back are left-handed hitters and they pose problems if you don't have some lefties to combat them. They're going to get you. It was just a bad night."
The Phils scored three more in the sixth, when Mayberry hit his two-run homer, and one each in the seventh and eighth innings to pad their lead.
"You never have enough runs," Kratz said. "You can never count out a lineup like that. The reason they're in first place in the National League [Central] is they score runs. They come after you just like we came after them. Hopefully, [Tuesday] we can do the same thing with [Reds righty Homer] Bailey coming out there. We've got Cliff [Lee] going. So that's our goal now."