San Francisco scored seven runs before their first out of the game, with Chili Davis' two-run double sparking a seven-run inning as the Giants won their sixth straight with a 10-3 romp past visiting Los Angeles.
Chris Brown led San Francisco's 14-hit attack with four hits and three runs scored. Davis had three RBI.
The last time the Giants (10-4) were in first place this late in the season was Aug. 13, 1978.
Los Angeles starter Dennis Powell (0-3) gave up a walk and four straight hits, including Davis' double. Then reliever Carlos Diaz gave up three hits and a walk before Dan Gladden -- the 10th batter in the inning -- hit into a run-scoring forceout for the Giants' first out.
Cubs 3, Cardinals 2: Ryne Sandberg's sacrifice fly in the ninth scored Manny Trillo to give Chicago its first home victory this season.
A walk to Bob Dernier and wild pitch by Cardinals reliever Pat Perry (1-1) started the Cubs' ninth. With Todd Worrell pitching, Trillo hit a sacrifice bunt, but Dernier beat the throw to third. After an intentional walk and fielder's choice, Sandberg hit a fly to center and Trillo beat the throw home. "I was just trying to get the ball in the air and get the run in," said Sandberg.
The Cubs took a 2-0 lead in the eighth, but the Cardinals' John Tudor, who has won 14 straight regular-season games, averted defeat when St. Louis tied in the ninth on Clint Hurdle's two-run, two-out triple.
Mets 7, Pirates 1: In New York, Bob Ojeda pitched a four-hitter through seven innings in his first NL start, Keith Hernandez and Gary Carter each drove in two runs and Ray Knight hit his second homer in two days. Ojeda (2-0) retired 12 in a row in one stretch.
Astros 3, Braves 2: Alan Ashby's leadoff homer in the ninth lifted Houston to victory in Atlanta. He hit his third homer of the season on a 2-2 pitch from reliever Duane Ward (0-1) over the right field fence.
Expos 8, Phillies 2: Tim Raines and Hubie Brooks each drove in two runs to pace Montreal to victory at home, sending Philadelphia to its fifth straight loss. Andre Dawson tied an Expos record by hitting a home run for the fourth time in his last four games.