"Sometimes when I get into trouble I do try to reach for something extra instead of pitching to location," Harden said.
"(Catcher Rob) Bowen had to come out once to slow me down. My goal is to be more efficient."
Harden (5-0) retired his first 14 batters before Shane Victorino singled cleanly into center field. Victorino got Philadelphia's other hit off Harden, an infield single with one out in the eighth.
"I've had games where I've felt better," Harden said. "In the past I've always had that one inning when I'd lose command suddenly. I want to get away from that. I was able to locate pitches and I felt good."
Harden's previous best for strikeouts was 10 against Tampa Bay on Aug. 31, 2003. He is the first A's pitcher to start a season 5-0 since Billy Koch in 2002, and he improved to 18-3 in 29 starts when pitching at least seven innings.
"I can't think of a more dominating performance than that one," A's manager Bob Geren said. "When he's on, he's almost unhittable."
Sidetracked by injuries during much of his career, Harden has made nine consecutive turns in the rotation for the first time in three years. He had not pitched eight innings since April 21, 2006, against the Los Angeles Angels.
"He pitched one of the better games against us this year if not the best," Phillies manager Charlie Manuel said. "We got beat by a good pitcher. They outhit us and outpitched us."
Harden threw 95 pitches, easily his most proficient outing of the season.
"He didn't leave too much over the plate for us," Phillies second baseman Chase Utley said. "It seemed like he could have gone longer."
Alan Embree completed the three-hitter, allowing Pat Burrell's two-out triple before retiring Ryan Howard on a groundout.
NL East-leading Philadelphia has lost seven of eight. Reigning NL MVP Jimmy Rollins struck out three times and made his first error in 40 games when he mishandled a grounder in the seventh.
Carlos Gonzalez homered for Oakland, which has won three of its last four series.
Adam Eaton (2-6) dropped to 0-4 in nine road games, allowing three runs and six hits in six innings.
"It would be nice to actually not give up a couple of runs in the first inning," Eaton said. "It's happened in four starts.
With what Harden did out there, it's tough not to fall right behind the 8-ball. Harden really had no-hit stuff; he had our number."
Oakland's first three batters reached: Mark Ellis walked and scored on an RBI double by Ryan Sweeney, who came around on Jack Cust's single. Sweeney then left the game due to a sprained left ankle and was sent for X-rays.
"His foot got caught up with the catcher and it swelled up quickly," Geren said.
Gonzalez homered for a 3-0 lead in the sixth. Jack Hannahan doubled in a run in the eighth against Tom Gordon and scored on an error by Victorino in center.
Notes: Harden has allowed more than three runs in only one of his 11 starts and improved to 31-0 in 38 starts when getting four or more runs of support. ... The Phillies have been successful on 23 consecutive steal attempts and lead the majors with a 90 percent success rate. ... Phillies OF Geoff Jenkins went 0-for-3 and is hitless in his last 26 at-bats. ... Athletics SS Bobby Crosby became the fifth Oakland player to record at least 25 doubles before the All-Star Break.
(Copyright 2008 by The Associated Press. All Rights Reserved.) AP-NY-06-26-08 1933EDT
