PHOENIX -- Keyvius Sampson earned his first major league victory, Cincinnati hit three home runs and the Reds beat Arizona 4-1 Saturday on the night the Diamondbacks retired new Hall of Famer Randy Johnson's No. 51.
All the Cincinnati runs came on homers by Eugenio Suarez, Brandon Phillips and Marlon Byrd, whose solo shot in the ninth was his 150th career home run.
Sampson (1-1) gave up a first-inning run but the Diamondbacks never scored again. He went six innings and allowed four hits, struck out four and walked three.
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Robbie Ray (3-7) pitched six innings for Arizona, allowing three runs and five hits. He matched his career high with eight strikeouts and walked one but fell to 0-3 in his last five starts.
Aroldis Chapman, hitting 103 mph on the Chase Field radar gun, threw a scoreless ninth for his 24th save in 25 tries.
Sampson lost his only other start, despite a solid outing in Pittsburgh's 3-0 win over the Reds last Sunday. He pitched a perfect inning of relief in his major league debut on July 30.
The Reds, shut out in their previous two games, scored all three runs off Ray with two outs. Suarez hit a two-run homer in the fourth, and Phillips added a solo shot in the fifth.
In the fourth, Byrd hit a bloop double down the left-field line and, on the next pitch, Suarez homered to put the Reds up 2-1. Phillips lined a 3-2 pitch just over the left-field wall to make it 3-1.
Arizona scored in the first when A.J. Pollock doubled to right and scored on David Peralta's single.
The Diamondbacks had runners on first and second with one out in the fourth and again in the fifth. In the fourth, Sampson escaped the jam with consecutive flyouts to right by Aaron Hill and Nick Ahmed. Paul Goldschmidt grounded into a double play to end the fifth.
Reds: RHP Anthony DeSclafani (7-7, 3.71 ERA) goes for his third consecutive win in the series finale Sunday.
Diamondbacks: LHP Patrick Corbin (2-3, 3.99) looks to bounce back from his worst start since coming back from Tommy John surgery. He gave up three runs in 1 1-3 innings at Washington on Tuesday.