PHOENIX — Alfonso Soriano hit a pair of leadoff homers and Carlos Zambrano bounced back from his first loss in 18 starts, lifting the Cubs to a 4-2 win over the Arizona Diamondbacks on Friday night.Soriano led off the fifth and seventh innings with homers against Armando Galarraga (3-2), and Geovany Soto hit a solo shot of his own to help the Cubs end a four-game losing streak.Zambrano (3-1) was sharp after his 10-game winning streak ended against the Los Angeles Dodgers on Sunday, settling in after giving up a long two-run homer to Justin Upton in the first inning to win his ninth straight road start.Carlos Marmol worked a perfect ninth for his sixth save in eight chances.Arizona took a step toward erasing its first-inning woes this season against the Cubs in the series opener on Thursday, scoring seven runs — four on Stephen Drew’s grand slam — off Ryan Dempster on the way to an 11-2 win. The Diamondbacks had been outscored 26-9 in the opening frame the previous 23 games.Arizona did it again against Zambrano, though not as emphatically, getting two runs in the first on a homer by Upton that almost landed in the restaurant at the back of the second deck in left. The shot, estimated at 455 feet, was one of three hits for Upton.Zambrano shook off the early drive and settled into a bit of a rhythm, stranding runners over the next four innings before pitching a perfect sixth. He was lifted for a pinch-hitter the next inning after allowing two runs on four hits and walking three.The Cubs went up 4-2 in the eighth when Aramis Ramirez squibbed a fielder’s choice against Esmerling Vasquez.Galarraga was solid through the first four innings, scattering three singles, including two that didn’t get out of the infield.He found trouble to start the fifth, when Soriano dug out a 1-2 breaking ball from just above the dirt and lined it over the wall in left-center. Soto followed with a no-doubt shot in the same vicinity, giving the Cubs back-to-back homers for the first time this season. Soriano did it again in the seventh, hitting Galarraga’s first pitch just over the wall in right-center for his ninth of the season to put the Cubs up 3-2. Galarraga was lifted for a pinch-hitter in the seventh after allowing three runs and six hits. Decent, but Zambrano was just a little better.

NOTES—Carlos Pena, stuck in a 2-for-25 slump, was held out of the lineup and entered the game as a defensive replacement in the ninth inning. … Soriano has 27 career multihomer games. … Arizona had scored 21 runs in 21 innings for Galarraga in his first four starts.