Pinch hitter Neil Walker pulled a seventh-inning, go-ahead RBI double down the right field line, leading the host Miami Marlins to a 4-2 win over the San Francisco Giants on Wednesday night.

The Marlins have the worst record in the National League, and the Giants own the second-worst mark. However, the Marlins have won nine of their past 12 games, and the Giants have dropped seven straight contests.

Jorge Alfaro, who scored the go-ahead run on Walker's double, went 4-for-4 to lead Miami's offense. It was the first four-hit game of his career.

Starlin Castro hit a triple in the eighth inning. It was Miami's first triple of the season, making the Marlins the last NL team to get its first three-bagger. Also on Wednesday, the Cleveland Indians became the last American League team to hit a triple, getting three against the Boston Red Sox.

Marlins rookie center fielder Harold Ramirez, who has been hot since making his major league debut on May 11, went 1-for-4 with an RBI and is batting .400. He has a nine-game hitting streak.

Reliever Nick Anderson (2-2) earned the win with one scoreless inning. Sergio Romo pitched the ninth -- allowing one run -- to earn his 11th save.

Marlins starter Pablo Lopez got a no-decision despite a strong effort. He allowed four hits, one walk and one run in six innings, striking out five.

Four-time All-Star Madison Bumgarner (3-5), the subject of numerous trade rumors, took the loss. He allowed six hits, one walk and two runs in six-plus innings. Bumgarner fanned four.

Miami opened the scoring in the third inning. Austin Dean hit a leadoff single, went to third on Brian Anderson's hit and scored on Castro's sacrifice fly.

San Francisco tied the score 1-1 on Brandon Belt's home run in the fourth, his eighth of the season. He pulled a 2-1 changeup to right-center for his first homer and RBI since May 18.

Miami took the lead in the seventh on Walker's double and added one more run on Garrett Cooper's sacrifice fly.

The Marlins extended the margin to 4-1 in the eighth as Castro tripled and scored on Ramirez's RBI single.

Belt's RBI groundout in the ninth closed the scoring.

--Field Level Media