CINCINNATTI -- Edwin Encarnacion hit his second career grand slam off Barry Zito, and Chris Dickerson homered and drove in four runs Friday night, leading the Cincinnati Reds to an 11-7 victory over the San Francisco Giants.

The Reds' best offensive showing since they traded Ken Griffey Jr. and Adam Dunn helped All-Star right-hander Edinson Volquez (16-5) get another milestone win, while Zito (8-16) hit yet another low point.

Volquez has pulled out of a midseason slump, winning three of his last four starts. This one wasn't his best -- six runs in 5 1-3 innings -- but was good enough to help the Reds get only their ninth victory in their last 32 games.

No pitcher has won more games in his first season with the Reds since 1988, when left-hander Danny Jackson won 23.

The game also was a reference point for Zito, having by far the worst season of his career. He was sent to the bullpen for a week after the Reds roughed him up for eight runs in only three innings on April 27, leaving him 0-6 in six starts at that point.

The 2002 AL Cy Young winner bottomed out at 0-8 before finally winning a game. He's the first major leaguer to lose 16 games this season.

Encarnacion hit a grand slam in the third inning off Zito, who left his first pitch right down the middle. The Reds scored four more in the fourth, when the Giants botched a rundown and Zito made an errant throw to first base on Volquez's sacrifice bunt to set up the rally.

Dickerson doubled home a pair of runs, and Zito hit Joey Votto with the bases loaded to force in another run and end his outing. The left-hander gave up eight runs -- seven earned -- in 3 1-3 innings, a line eerily similar to that first outing against Cincinnati.

Dickerson added a two-run homer off Billy Sadler that put the Reds in double-digits for the first time since July 10, when Griffey and Dunn homered in a 12-7 win over the Cubs at Wrigley Field. The Reds traded Griffey to the White Sox on July 31, and sent Dunn to Arizona on Aug. 11.