Giants 6, Marlins 4: Michael Morse belted a two-run homer and Matt Cain earned his first win in seven starts as San Francisco edged visiting Miami in the opener of a four-game series.

Morse went 3-for-4 and drove in three runs for the Giants, who have won 16 of their last 21 games. Cain (1-3) allowed four runs while striking out seven over 7 2/3 innings, and Sergio Romo retired the Marlins in order in the ninth for his 14th save.

The Marlins staked Nathan Eovaldi (2-2) to an early lead on Derek Dietrich’s solo homer in the first and Garrett Jones’ two-run blast in the second. Casey McGehee’s RBI double put the Marlins ahead 4-1 in the third before Morse went deep in the bottom half off Eovaldi, who yielded six runs on nine hits over 4 1/3 innings.

The Giants claimed the lead with three runs in the fifth when Buster Posey doubled in two runs and scored on Morse’s single to shallow center field. Hunter Pence contributed three hits and scored twice for San Francisco, which finished with 12 hits and won for the 11th time in their last 14 games at AT&T Park.

Reed Johnson had two hits and is 9-for-20 over his last six games for Miami, which has lost six of its last seven. Marlins catcher Jarrod Saltalamacchia went 0-for-4 with two strikeouts and is hitless in his last 26 at-bats.

GAME NOTEBOOK: Giants RHP Yusmeiro Petit will start Friday in place of RHP Tim Hudson, who has been scratched due to a strained left hip. Hudson is not expected to require a trip to the disabled list. … Miami RF Giancarlo Stanton went 1-for-3 to extend his career-best hitting streak to 17 games. … San Francisco improved to 11-3 in the opening game of a series.