Adam LaRoche slammed a pair of home runs and drove in five runs, powering the Arizona Diamondbacks to a 13-5 rout of the Chicago Cubs in the opener of a four-game series Thursday.

Kelly Johnson hit his league-leading ninth home run and Chris Snyder belted a two-run shot as the Diamondbacks sent the Cubs to their third consecutive defeat.

Ian Kennedy (1-1) was the beneficiary of the offensive explosion, earning his first victory of the season and the second of his career. It was Kennedy’s first win since Sept. 1, 2007, when he was with the New York Yankees.

He handcuffed the Cubs lineup until surrendering Kosuke Fukudome’s grand slam in the eighth inning. Kennedy allowed five runs on six hits and struck out six in eight innings.

Coming off a stirring 12-11 victory over Colorado on Wednesday, the Diamondbacks carried the momentum into Thursday’s game, shelling Cubs starter Ted Lilly (1-1) for six runs and seven hits in five innings.

With a strong wind blowing out, LaRoche hit a three-run shot and Snyder added a two-run blast in a five-run fourth to stake Arizona to a 5-1 lead.

Johnson’s three-run homer capped a seven-run seventh that padded the cushion to 13-1.