SAN DIEGO - Flash back 2 weeks: The Phillies had just finished off a four-game sweep of the Nationals, but it had come in a disconcerting manner, with a potent offense carrying a struggling starting pitching staff that had just suffered perhaps its worst performance of the year - a 1 1/3- inning outing in which righthander Chan Ho Park allowed five runs.

Last night, as J.A. Happ's long left arm whipped again and again and again through the cool night air, all of it seemed a distant memory.

It seemed fitting that the man whose induction into the rotation occurred on that mid-May night in Washington was on the mound last night at Petco Park, delivering the most impressive performance yet out of this rejuvenated group of starters. For seven scoreless innings of the Phillies' 5-1 win, the slender lefty bedeviled an overmatched Padres line-up, retiring 14 of the last 16 batters he faced and holding the Padres to just four inconsequential hits.

"He's the kind of pitcher I expected," said manager Charlie Manuel. "He goes right at you. He doesn't back off."

Even as former No. 2 starter Brett Myers undergoes hip surgery today in New York, at which point his season likely will end, the performance of this rotation has never been brighter. Since that May 18 game against the Nationals, when their ERA ballooned to a league-worst 6.35, the team's starters have allowed just 41 earned runs in 91 innings. That's an ERA of 4.06, more than two runs better than the aforementioned mark.

In all but two of the past 15 starts, a starter has pitched into the sixth inning, and in all but four a starter has finished the sixth.

Not coincidentally, the Phillies have won 11 of those 15 games, including last night's cakewalk that capped a sweep of the Padres and extended their win streak to a season-high six games.

Happ became the sixth straight starter to record a victory, striking out four and walking two while throwing a season-high 112 pitches. The 26-year-old lefty received some help in the second inning, when rightfielder Greg Dobbs made a terrific running stab of a Chris Young line drive that came with two outs and the bases loaded and looked sure to score three runs.

"Dobber really turned the game around right there," said Happ.

But aside from a diving stop by Jimmy Rollins with two outs in the third inning and a nifty doubleplay turned by Rollins and Chase Utley in the sixth, Happ thrived on his own. Besides the second inning, the only other time the Padres had a runner in scoring position against him was the seventh, when Brian Giles reached second after dropping a bloop hit into a vacant patch of grass between a charging Raul Ibanez and a retreating Rollins.

By that point the Phillies led 5-0, thanks to a two-run home run by Ryan Howard in the first inning, a sacrifice fly by Pedro Feliz in the fourth, and two more runs in the seventh. Happ didn't need the cushion. He struck out Nick Hundley on his 103rd pitch of the evening, then got Will Venable and Chris Burke to fly out to end the frame.

Happ, now 4-0 with a 2.47 ERA overall, has allowed just five runs in his past 28 2/3 innings, 18 1/3 of them as a starter.

For the third straight night, everything seemed to work in order for the Phillies. Howard homered for the 16th time this season, Ibanez extended his league-leading RBI total to 52, and Dobbs took advantage of his first start of the season in rightfield, hitting a ground-rule double in the second and a single to center in the fourth while finishing 2-for-4.

Jayson Werth, who entered the night mired in an 8-for-55 slump, hit an RBI single in the seventh after entering for Shane Victorino, who left the game with a left hip strain that will be re-evaluated today.

Lefthanded reliever J.C. Romero returned from his 50-game suspension in the eighth inning and gave up one unearned run in 1 1/3innings, with two hits, one walk and a strikeout.

The Phillies in first place in the NL East, three games ahead of the Mets, 11 games over .500, and looking more like the complete team Manuel and his front office envisioned they had at the start of the season.

Most important, a rotation that still must find a permanent answer to replace Myers is in a groove.

With a four-game series against the Dodgers, who have the best record in the majors, set to start tonight, the Phillies hope it stays that way. *

For more Phillies coverage and opinion, read David Murphy's blog, High Cheese, at http://go.philly.com/highcheese.