When Roy Halladay is at his best he can frequently help overcome the offensive inefficiency of the Phillies. These days if the righthander isn't totally on his game, winning can be an iffy proposition.

For the second straight outing, Halladay wasn't his usual dominating self, and coupled with another lackluster offensive effort it equaled the end of the Phillies' modest two-game winning streak.

Halladay allowed three runs in seven innings as the Chicago Cubs defeated the Phillies, 5-1 on Friday in the first of a four-game series at Citizens Bank Park.

In Halladay's last start, he also took the loss after allowing just two runs in seven innings of a 5-1 defeat at San Diego.

All three runs that Halladay surrendered were earned. He allowed six hits, struck out five, and walked two while throwing 113 pitches, 73 for strikes.

"I felt like we made good pitches all night," Halladay said. "They were scrappy - they obviously have some speed and were able to capitalize on it."

The first inning provided an indication of things to come when the Phillies had runners at the corners with nobody out against lefthander Paul Maholm but failed to score. Juan Pierre opened with a single, then advanced to second on a wild pitch and to third on Placido Polanco's single.

Jimmy Rollins fouled out to the catcher, Hunter Pence popped up to the shortstop, and Shane Victorino ended the inning on a groundout.

"We had a chance in the first inning and couldn't knock the runner in from third and it kind of went downhill from there," manager Charlie Manuel said.

Halladay retired the first 10 batters before Chicago centerfielder Tony Campana broke up the perfect game with one out in the fourth inning on a drag bunt single to first base.

Phillies first baseman Ty Wigginton fielded the ball, but Campana safely slid head first. Campana then stole second and scored on Starlin Castro's bloop single to center.

Castro, a notorious bad-ball hitter, went far out of the strike zone to get a piece of a curveball.

Chicago added two runs in the sixth on Alfonso Soriano's RBI single off a 91 m.p.h. fastball and Ian Stewart's RBI double on an 0-2 cutter.

"It was one of those games where you control what you can and try to put the ball in play and put it on ground and we did that with the exception of the Stewart hit which was a good cutter where we wanted it," Halladay said.

The Phillies got to Maholm in the seventh when Wigginton, who extended his hitting streak to 12 games with a fourth inning single, crushed a 2-2 fastball to left for his second home run of the season.

That ended Maholm's evening. He threw 61/3 innings and allowed five hits, one run and no walks, and struck out one. A former Pittsburgh Pirate, Maholm entered the game with an 8.36 ERA.

The Phillies continued to rally in the seventh, putting runners on first and second with two outs, following infield singles by Galvis and John Mayberry Jr., who was pinch-hitting for Halladay.

Lefthander James Russell then got Juan Pierre to end the inning on what was almost an adventure fly ball to Soriano in left.

Soriano originally misjudged the ball, coming in, but he retreated in enough time to make the inning-ending catch.

Chicago added two runs in the ninth off Michael Schwimer on an RBI triple by Reed Johnson to right that eluded a diving Pence, and an RBI single by David DeJesus.

Contact Marc Narducci at 856-779-3225, mnarducci@phillynews.com or follow on Twitter @sjnard.