Grand Junction's bats were shut down in the first of a four-game series at Billings, Montana, falling to the Mustangs 6-0 on Monday night.
Helcris Olivarez had a strong performance on the mound for the Rockies (26-25, 7-6 second half), tossing five shutout innings and striking out five batters.
Anderson Pilar (3-2) relieved Olivarez to start the sixth and kept up the shutout until the seventh inning, when the scoreless tie was finally ended.
T.J. Hopkins hit a two-run single and Eric Yang added two more runs on a double to put the Mustangs (24-28, 9-5 second half) up 4-0 going into the eighth.
The Rockies continued to struggle at the plate in the top of the eighth, and Billings added insurance in the bottom frame on a two-run double by Reyny Reyes.
Rocky on the move
Cristopher Navarro was promoted to Colorado's Low-A affiliate, Asheville, and made his debut Monday night.
He hit .333 in his past 10 games with Grand Junction and kept up that pace in his first game as a Tourist. He had two hits and two RBI in Asheville's 11-6 win over the Rome Braves.