PHOENIX, Arizona (Reuters) - The Arizona Diamondbacks pounded the Cincinnati Reds 13-2 to make it a happy home opener on Friday.

Kelly Johnson hit a three-run homer in the eighth inning where the Diamondbacks (3-3) scored six times to punctuate their victory while making a good start to a nine-game home stretch.

"Great atmosphere," Arizona manager Kirk Gibson told reporters. "You wish they could all be this way."

Justin Upton homered and scored three times and Miguel Montero finished 3-for-3 with two runs as Arizona's offense exploded to give starting pitcher Ian Kennedy more than enough run support.

Kennedy struck out nine batters and allowed one run in eight innings to earn his first win of the season.

"I was throwing a lot of strikes," Kennedy said. "The big part was keeping them off balance."

The Reds (5-2) lost their second in a row after beginning the season 5-0.

Reds starter Travis Wood was chased after allowing six runs in five innings and reliever Matt Maloney was charged with seven runs in just 1 2/3 innings.

Cincinnati fell behind 3-0 after the second inning and Arizona added three runs in the sixth and one in the seventh before the huge eighth inning.

Reigning National League MVP Joey Votto went 2-for-4 with a solo home run in the ninth for the Reds.

Montero is off to a strong start for Arizona this season, batting .545 thus far.

Shortstop Stephen Drew made his first start of the season and had an RBI double for Arizona after an abdominal injury had kept him sidelined.

(Editing by Peter Rutherford)