CHICAGO –  Alfonso Soriano hit a two-run homer that landed on Waveland Avenue and Anthony Rizzo added a solo shot, helping Chris Volstad and the Chicago Cubs beat the weary San Francisco Giants 6-4 on Friday.

Soriano also had a two-out RBI single in the first as Chicago earned its first win of the season against the NL West leaders in five tries. The Cubs were swept in a four-game series at San Francisco in June.

Volstad (2-9) allowed two runs and five hits in 5 2-3 innings for his second consecutive victory after a 24-start winless streak.

Buster Posey went 3 for 3 with two RBIs for San Francisco, which had won a season-high six consecutive road games.

The Giants rallied for an 8-4 victory in Houston on Thursday night, then arrived in Chicago around 3 a.m. They mostly stayed in the visitors' clubhouse while the Cubs took batting practice, but still looked listless for much of the muggy day at Wrigley Field.