Franklin Stubbs hit his third home run in three days and Orel Hershiser pitched a seven-hitter as the Dodgers ended a three-game losing streak by beating the San Francisco Giants, 3-2, yesterday in Los Angeles.

With the game tied at 1 in the seventh, Mariano Duncan reached base on shortstop Jose Uribe's error. Stubbs, who had struck out twice and walked, hit a 1-2 pitch into the center field stands. It gave Stubbs nine RBI in the last three games.

It was the Dodgers' seventh straight one-run game, tying the major league record at the start of a season set earlier in the day by San Diego in a 7-6 triumph over Cincinnati.

*Pirates 8, Cubs 0: Mike Brown drove in four runs, including a three-run homer after a botched Chicago double play, and Pittsburgh, at home, won behind the four-hit pitching of Rick Reuschel and two relievers.

Johnny Ray, batting .529 in four games with eight RBI, had two doubles and a single and drove in three of the first four runs as the Pirates handed the Cubs their fourth loss in five games.

*Padres 7, Reds 6: Marvell Wynne hit his second home run of the game leading off the bottom of the ninth inning to give San Diego the victory at home.

Wynne, who homered as a pinch hitter to lead off the seventh, hit a 2-1 pitch from Joe Price over the right field wall. It was the first two-homer game of his career for the outfielder, who hit only two all last season with Pittsburgh.

Wynne's second homer made a winner of Rich Gossage, who pitched the final two innings and was tagged for a game-tying home run in the top of the ninth by rookie Kal Daniels.

*Phillies 4, Mets 2: Darren Daulton and Gary Redus hit home runs to back Shane Rawley's 10-hit pitching as Philadelphia won at home.

Rawley (1-0) walked one and struck out one in a game played in a steady drizzle. He lost his shutout bid in the eighth on doubles by Keith Hernandez and Gary Carter. New York's Ray Knight hit his second homer in as many games in the ninth.

*Braves 8, Astros 7: Billy Sample had three hits, including a controversial three-run homer in the fourth inning, Ken Oberkfell drove in four runs and Gene Garber pitched out of a ninth-inning jam to lead Atlanta to victory in Houston.

Third base umpire John McSherry ruled that Sample's home run was just inside the foul pole, prompting a heated protest by Houston Manager Hal Lanier.

Atlanta's Dale Murphy did not start in center field for the first time since since 1980. Instead, he opened the game in right field.

*Expos 3, Cardinals 2: Montreal's Mitch Webster and Herm Winningham hit homers and Bryn Smith allowed three hits in six innings, handing St. Louis, at home, its first loss of the season in five games.