#21-Ryan Blaney was fastest during opening practice at Phoenix with a speed of 131.368mph.
The rest of the top 10: #7-Justin Allgaier, #19-Matt Tifft, #9-William Byron, #23-Spencer Gallagher, #18-Christopher Bell, #00-Cole Custer, #20-Erik Jones, #11-Blake Koch, and #2-Austin Dillon.
37 drivers practiced during the session.
See complete results on the Phoenix practice 1 speeds page (pdf).
