Giants 5, Reds 3: Pablo Sandoval doubled in two runs during a three-run first inning as San Franciasco earned a split of the doubleheader at AT&T Park.

The Giants moved ahead 4-0 on a sacrifice fly by Gregor Blanco in the second inning and held on for their first win in six meetings with Cincinnati this season. Santiago Casilla (4-3) worked 1 1/3 scoreless frames for the win and Sergio Romo recorded the final four outs via strikeout for his 24th save.

After winning the opener 9-2, the Reds played as the home team in the nightcap, which was the makeup of a rainout on July 4 in Cincinnati. Greg Reynolds (0-1), who was making his first start since 2011, yielded five runs and eight hits over five frames.

The Reds halved the deficit in the second on Corky Miller's two-run double before the Giants got back a run on Brandon Belt’s groundout in the fifth. Todd Frazier, who went 3-for-5 and has seven hits and six RBIs in the first three games of the series, delivered an RBI double in the bottom half to get Cincinnati within 5-3.

Cincinnati had runners on first and second with two outs in the eighth when Giants manager Bruce Bochy called upon Romo, who struck out Brandon Phillips to end the threat. Romo’s four-out save helped Bochy become the 21st manager in major-league history with 1,500 career victories.

GAME NOTEBOOK: San Francisco was outscored 34-6 while losing its first five meetings with the Reds. ... Giants starter Barry Zito allowed three runs over 4 2/3 innings and remained winless since May 30. ... The Giants scored three runs in the first inning for the first time since May 4 against the Los Angeles Dodgers.