The win moves Philadelphia within four games of Atlanta in the crowded National League East. Halladay earned his 10th win of the year by limiting the Braves to five hits and one run with one walk and seven strikeouts.
"It is an important series for us," Halladay said.
Third baseman Greg Dobbs, filling in for the injured Placido Polanco, hit a go-ahead two-run homer in the sixth for Philadelphia, which had been shut out to that point by Atlanta starter Derek Lowe. Lowe allowed two runs in seven innings, but took the loss in the duel.
"You can't hang your head when a guy pitches like that," Lowe said. "He's one of the best in the game."
In the dugout before the game, Manuel spoke about the importance of this crucial homestand for Philadelphia before next week's All-Star break. In some ways, perhaps, he was also building up some intensity to see how Halladay would react.
He'd take some more reactions like that.
"He is a horse," Manuel said. "The pitches he can throw, where he takes you in a game, all of that. I feel, especially, like after we scored some runs the crowd really got into it. There was a lot of energy going around there, especially at the end. Roy is good. He's going to win a lot of games for us."
It was Halladay's Major League-leading seventh complete game already this season -- he had nine last year -- and he needed only 93 pitches to do it. He threw only six pitches in the ninth to close out the game, and his 93 were the third-fewest pitches he has thrown in a complete game in his career. To put it into perspective, just three teams have as many or more complete games than Halladay, and he's now just the sixth pitcher since 1993 to have seven complete games at the season's midpoint.
"I think as the game progressed, you realize it's going to be a close game," Halladay said. "It's like a lot of them -- you're trying to minimize as much you can and keep yourself in it. We scored just enough."
Halladay may have had a different edge to him on Monday, too, after allowing a career-high 13 hits and four runs in a loss against Cincinnati on Wednesday. That game had represented a frustrating low for the All-Star pitcher this season, who fell to 9-7 with the defeat, and he expressed it afterward.
"I think you go out there trying to win every time," Halladay said. "But definitely from a numbers standpoint and the standings, it's important to win games in your division. From my approach, I went out the same way. But it is an important series for us."
He gave up a solo home run to Chipper Jones in the first inning -- a first-pitch fastball Jones drove to left-center field for his sixth of the year -- but scattered only four hits after that. A key defensive play came in the eighth, when catcher Dane Sardinha threw out Gregor Blanco trying to steal second base with nobody out.
Halladay called that "the play of the game," and it illustrated how the Phillies managed to get another big play from some unlikely sources.
"I thought maybe they might be bunting there to get him over in a one-run game," Sardinha said. "It might have been a hit-and-run. Good thing we threw a cutter in on him, because that's a tough pitch to run on."
Until the sixth, though, Philadelphia trailed and looked on its way to wasting another strong Halladay performance. Dobbs drove the first pitch he saw from Lowe deep into the right-field seats for his second home run this season.
"I was really just looking for something up in the zone," Dobbs said. "He does such a good job of throwing those pitches down below your knees and to your ankles. He's a great sinkerball pitcher. I was just looking for something up that I could drive."
Phillies infielder Juan Castro added the insurance run in the eighth with an RBI single, snapping an 0-for-12 streak and giving him his first RBI since June 13.
It was an added run, but Halladay didn't need it. Dobbs' clutch homer had given him enough to win his first true test in the spotlight.
"He's amazing, he's been amazing all year," Dobbs said. "To give him that support is huge."