CHICAGO (AP) — Ryan Vogelsong pitched six scoreless innings in a rain-shortened game for his first career shutout and Buster Posey hit an RBI single to lead the San Francisco Giants to a 3-0 win over the Chicago Cubs on Saturday night.

The Giants scored two runs on two errors by the Cubs, and have won seven of their last eight. The game was delayed two pitches into the seventh inning and called after a 40-minute delay.

READ MORE: Delivery Driver Shot In Head In Back of The Yards; 18-Year-Old Struck In Thigh

Vogelsong (3-0) allowed seven hits and struck out seven in his first complete game. He was also helped by two double plays as the Cubs left eight runners on.

Doug Davis (0-1) pitched five innings in his season debut and allowed three runs – one earned – and four hits. He struck out six and walked one, and was hurt by three errors behind him.

In his last start, Vogelsong was perfect through five and allowed one hit and one walk over 6 1-3 innings of a 3-0 win against Colorado. Vogelsong, who dropped his ERA to 2.36, struck out Alfonso Soriano with the bases loaded to end the first inning, and fanned Carlos Pena with two runners on in the fifth.

The Cubs played its first Saturday night game at Wrigley Field in nearly nine years. Because of parking restrictions in the neighborhood, the Cubs may only play on Friday and Saturday nights if it is part of a national television broadcast. This was the first Saturday night game at Wrigley since Aug. 31, 2002, and the game was played under brutal conditions. The game-time temperature was 43 degrees and the wind was blowing in at 19 mph with a constant drizzle throughout the game until the rain picked up in the seventh. Most of the announced crowd of 39,706 that showed up left by the fifth inning.

READ MORE: Toys For Tots Motorcycle Parade Delivers Presents For Children

With starters Andrew Cashner and Randy Wells on the disabled list, Davis filled the void at the back of the Cubs’ rotation – and it marked a much-anticipated return for him. A year ago Sunday, Davis was diagnosed with pericarditis, an inflammation of the lining surrounding the heart. He made one more start in July before being shut down the rest of the season with elbow problems.

Davis made his first start after being promoted from Triple-A Iowa. The veteran left-hander went 1-4 with a 7.51 ERA in eight starts for Milwaukee last season.

With one out in the first inning, Freddy Sanchez drove a double over the head of right fielder Kosuke Fukudome. One out later, Posey singled to left. Sanchez was going to score easily from second, but left fielder Soriano made an ill-advised throw to the plate, and Posey took second on the throw then advanced to third on catcher Koyie Hill’s throwing error. Davis got Cody Ross to ground out to limit the damage. Posey came in 6 for 32 against lefties.

The Giants took advantage of some shoddy Cubs defense in the third inning. With the bases loaded and two outs, Ross hit a slower roller off home plate. Hill fielded the ball and his throw took Pena off first base allowing Vogelsong to score. It was Hill’s second error of the game. Mark DeRosa followed with a grounder to third baseman Blake DeWitt, who made another errant throw to first to allow Aaron Rowand to score to make it 3-0.

Cubs second baseman Darwin Barney made a highlight-reel over-the-head diving catch in foul territory on Miguel Tejada’s ball in the fourth.

MORE NEWS: Chicago Weather: Monday Brings Wind, Blast Of Cold Air

Notes: Cubs 3B Aramis Ramirez was not in the starting lineup after his flight was delayed. Ramirez was in the Dominican Republic for personal business matters. … Cubs OF Marlon Byrd extended his hitting streak to 15 games after an infield single in the fourth. It matched his longest of his career set in 2003. … Giants OF Andres Torres had the night off.

© 2011 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.