Cubs 2, Giants 0 (5): Anthony Rizzo homered and Tsuyoshi Wada pitched five solid innings to lead host Chicago to a rain-shortened victory in the opener of the three-game series.

Rizzo blasted his 29th homer out to right-center field in the first inning, cranking a 2-0 changeup from Ryan Vogelsong (7-9) onto Sheffield Avenue. That accounted for all the scoring as play was stopped in the middle of the fifth and the game finally was called after a delay of 4 hours, 34 minutes due to unplayable conditions, prompting the Giants to say they will most likely protest the contest.

Rizzo recorded two of the Cubs' three hits, with Arismendy Alcantara notching the other. Angel Pagan and Joaquin Arias had two hits apiece for the Giants, who slipped 4 1/2 games behind the first-place Los Angeles Dodgers in the National League West and fell into a tie with Atlanta for the final wild-card spot.

Wada (3-1) wiggled out of trouble effectively, allowing six hits in an abbreviated complete game to win his third straight decision. He worked around one-out doubles in the first and fifth while stranding two runners in scoring position in the second.

Heavy rain moved in while the Giants were batting in the top of the fifth, and the Wrigley Field grounds crew struggled to move the tarp into place during the driving rain in the middle of the frame. The deluge only lasted about 15 minutes, but the infield took on a substantial amount of water and the crew was unable to get the surface back into playable condition.

GAME NOTEBOOK: San Francisco LF Michael Morse struck out in the second inning, ending his strings of hits in seven straight at-bats and reaching safely in nine consecutive plate appearances. … Giants C Hector Sanchez could be done for the season, as he was diagnosed with a concussion after taking a foul tip off the mask Saturday while on a rehab assignment following a previous concussion that landed him on the disabled list July 26. … Vogelsong allowed two runs and three hits in a four-inning complete game.