Colin Simpson hit his 13th home run of the season and drove in four runs Thursday night to lead Grand Junction to an 8-3 win at Great Falls.
Simpson, who was the runner-up in the Northwest-Pioneer League All-Star Home Run Derby earlier this week, put Grand Junction up 8-0 with his three-run home run in the second inning.
The Rockies (26-22, 7-3) scored all eight runs in the first two innings and relied on another outstanding start from Anderson Amarista (3-3).
The right-hander from Venezuela scattered five hits over seven innings, struck out six and walked only one. Amarista allowed three runs, a home run to Sam Abbott in the second inning and a two-run triple by Kelvin Maldonado in the fifth.
Christian Koss, the Pioneer League player of the month for July, continues to hit the ball well, with an RBI triple to score Eddy Diaz in the first inning. Koss, now hitting .391, came home on a base hit by Simpson, who scored on Brenton Doyle's single to right.
Diaz reached on a fielder's choice in the second to score Owen Taylor, and Ronaiker Palma came home on Julio Carreras' base hit before Simpson's home run to right-center.
Zach Guth and Juan Mejia each threw one scoreless inning of relief for Grand Junction, which could have blown the game open, but left 23 men on base.