Halladay (10-3) gave up eight hits and walked none in tying for the major league high in victories. He struck out four, raising his NL-topping total to 123.
The Phillies have won each of Halladay's last eight starts and the right-hander is 5-0 with a 2.64 ERA during the stretch. He improved to 30-3 in a Philadelphia uniform in the 35 starts in which the Phillies have given him the lead.
Josh Outman (3-2), a former Phillies minor leaguer, allowed three runs and eight hits in six innings. He was picked by the Phillies in the 10th round of the 2005 draft and traded to Oakland in 2008 as part of the deal for Joe Blanton.
The Phillies started the game with three straight hits off Outman. Rollins singled, Polanco doubled, Shane Victorino hit an RBI single and Ryan Howard had a double-play groundout that scored a run for a 2-0 lead.
Oakland got on the board in the fourth when Coco Crisp singled and later scored on Ryan Sweeney's bloop single.
The Phillies got that run back in the fifth on Ben Francisco's two-out infield single with the bases loaded. Outman cleanly fielded Francisco's slowly hit roller to the left of the pitcher's mound and looked to third to try to get Polanco, but third baseman Scott Sizemore was charging and not on the bag. By the time Outman turned and fired to first, it was too late to get Francisco.
The A's threatened in the seventh when Jackson led off with a single and, after an out, went to third on Sizemore's double down the right-field line. Jackson may have scored on the hit, but he appeared to hesitate rounding second. Oakland couldn't get the run home as Landon Powell popped out and pinch-hitter David DeJesus struck out looking. DeJesus has three hits in his last 38 at-bats (.079).
Philadelphia right fielder Domonic Brown, booed for failing to run out a grounder in Saturday's game, was not in the lineup on Sunday. Brown, who might not have started against the lefty Outman anyway, was replaced by Francisco.
Manager Charlie Manuel, however, could've elected to play Francisco in left field and sat slumping left-handed hitting Raul Ibanez, who entered 4 for 35 with no RBIs in his last 10 games. Ibanez, who hasn't homered in his last 23 games, went 1 for 4.
NOTES: Howard went 0 for 2 and is hitless in his last nine at-bats. But he stole his first base of the season in the seventh. ... Cliff Pennington went 0 for 4 for Oakland and is now hitless in his last 19 at-bats. ... Outman went 0 for 2, dropping A's pitchers to 0 for 18 this season. ... The Phillies recorded their 166th consecutive sellout and second-largest regular-season crowd with 45,863 fans.