SAN DIEGO - When J.A. Happ worked out every day last winter in a gym near his Chicago home, he wanted one thing, and he wanted it badly: To become a starting pitcher for the Phillies. Now that Happ has earned that job, he is determined to keep it.

The 26-year-old lefthander pitched seven scoreless innings and allowed four hits Wednesday night in the Phillies' 5-1 win over San Diego at Petco Park.

"Our starting pitching is getting more consistent," manager Charlie Manuel said. "Happ, tonight, when he can give you what he did, that's very good. I'm very happy with him."

The game also saw the return of reliever J.C. Romero from a 50-game suspension for violating the league's substance-abuse policy. Romero allowed two hits and an unearned run in 11/3 innings, and the Phillies won their sixth in a row while sweeping San Diego in a three-game series.

Happ has been excellent in two starts since he was promoted to the rotation in place of Chan Ho Park, who had edged Happ in a spring-training competition for the job.

His first start of the season came at Yankee Stadium on May 23, where he limited a powerful lineup in a hitter-friendly ballpark to two runs in six innings. On Friday, he allowed two runs in 5 1/3 innings to earn the win at home against Washington. Wednesday night's win was his finest performance yet.

"I just tried to be aggressive," Happ said when asked what had improved since his last outing. "I have to be aggressive to be successful. I mixed it up [with more breaking balls] early in the game, a little bit more and a little earlier. Kept them off-balance."

After Greg Dobbs rescued Happ from a second-inning jam, the pitcher was dominant. Happ allowed two singles in the second, then walked Chris Burke to bring up pitcher Chris Young with the bases loaded. Young, a more skilled hitter than most pitchers (he carried a .300 batting average into the game), launched a fly ball to deep right field.

The shot looked as if it would elude a racing Dobbs, making his first outfield appearance of the season. Dobbs ran toward the warning track, extended his arm, and snagged the ball with his back to the plate. A grateful Happ waited outside the dugout to thank Dobbs for saving a likely three runs.

"When I turned around and saw him sprinting, I thought, 'Yeah, that's probably going to [drop]," Happ said. "Dobber really turned the game around there. Gave me some confidence and made me focus in a little more."

After a leadoff single in the third, Happ retired 10 consecutive batters before walking Adrian Gonzalez with one out in the sixth. The next batter, Kevin Kouzmanoff, bounced into a double play. Happ allowed a leadoff double in the seventh, and again escaped with a scoreless inning.

The offense spotted the starter an early lead. Shane Victorino - who left in the sixth with a hip strain and will be reevaluated today - hit a one-out double in the first, and reigning National League player of the week Ryan Howard belted a home run to center field.

The Phillies added a run, and stranded two, in the fourth. Raul Ibanez led off with a single, moved to third when Dobbs singled, and scored when Feliz hit a sacrifice fly to left. Jimmy Rollins scored his team's fourth run in the seventh when he singled, stole second, and ran home on Jayson Werth's single. The Phils extended their lead to 5-0 when Ibanez reached base on a fielder's choice with the bases loaded, scoring Werth.

Romero took over in the eighth and allowed two hits, a walk and a run that was unearned because of a Chris Coste passed ball.

"He did fine," Manuel said. "He did his job. It was good to see him out there again."

Contact staff writer Andy Martino at 215-854-4874 or amartino@phillynews.com.