Desmond Jennings, Aristides Aquino and Brandon Dixon all homered for the Reds' split-squad team.
Jesse Winker, the Reds' No. 3 prospect per MLBPipeline.com, was 2-for-3 with an RBI triple, and shortstop Zack Cozart also had a pair of hits, including a double.
Reds southpaw Brandon Finnegan gave up six hits and three runs in 2 1/3 innings, while Seattle's Chase De Jong allowed four hits and three runs in his first Cactus League start.
Andrew Moore, the Mariners' No.