CHICAGO -- Buster Posey went 4 for 4 with his 14th homer, leading Madison Bumgarner and the San Francisco Giants to a 5-3 victory over the Chicago Cubs on Thursday night.
Pablo Sandoval added three hits and two RBIs as the Giants rebounded from a 2-1 loss earlier in the day in the resumption of their suspended game in the series opener.
Bumgarner (14-9) struck out 12 in seven innings. He allowed three runs and seven hits.
The long day started with a rain delay of 1 hour, 57 minutes, and then the Cubs and Giants played the final 4 1/2 innings of a game the Cubs thought they had won 2-0 on Tuesday night.
A short rainstorm caused a delay of more than 4 1/2 hours after the grounds crew struggled with the tarp. The umpires said the field was unplayable and called it at 1:16 a.m.
But the Giants protested, and Major League Baseball ruled that the tarp had not been properly put away after its previous use. The game was suspended.
It was the first successful protest in MLB since 1986.
Anthony Rizzo's two-run homer from Tuesday held up for Chicago. Joe Panik had an RBI single in the sixth to pull the Giants to 2-1, but Pedro Strop worked the eighth and Hector Rondon got three outs for his 19th save in 23 opportunities.
Tuesday's starters proved to be the pitchers of record. Tsuyoshi Wada (3-1) earned the victory for the Cubs, while Ryan Vogelsong (7-9) took the loss.
Chicago then got off to a fast start in the nightcap. Justin Ruggiano and Welington Castillo hit back-to-back homers in the first to give the Cubs a 3-1 lead.
But San Francisco grabbed the lead for good on Posey's leadoff drive to left in the fifth against Travis Wood (7-11). Michael Morse added a sacrifice fly in the seventh that made it 5-3.
Wood (7-11) gave up four runs and eight hits in six innings. The left-hander is 0-6 with a 5.45 ERA in his last 12 starts.
Touted Cubs prospect Javier Baez struck out four times, including with two out and two runners in scoring position in the seventh inning. Through 71 big league at-bats, Baez has struck out 31 times.
Santiago Casilla worked a scoreless ninth for his 11th save in 14 opportunities.
Cubs: RHP Edwin Jackson was placed on the 15-day disabled list with a right lat strain. Jackson dealt with a similar injury at the end of last season and hopes that by going on the DL now, he will be able to pitch again in September. ... SS Starlin Castro was placed on the bereavement list after leaving the team for a family emergency.
Giants: INF Ehire Adrianza has been slow to recover from a second strained groin injury, which raises doubts about his status in the final weeks of the season. "He's not ready yet, so that's another decision we'll have to make," manager Bruce Bochy said. ... Bochy was optimistic that 1B Brandon Belt and C Hector Sanchez would recover from concussions in time for the stretch drive.
Giants: RHP Tim Hudson (8-9, 3.03 ERA) faces off with Washington RHP Doug Fister (12-3, 2.20 ERA) as the Giants take on the Nationals on Friday in the opener of a weekend road series.
Cubs: RHP Jake Arrieta (6-4, 2.61 ERA) faces his former club when Baltimore comes to Wrigley Field for a weekend series. RHP Kevin Gausman (7-4, 3.70 ERA) goes for the Orioles.