The second-place finish came on the heels of leading 83 laps two weekends ago at Las Vegas Motor Speedway and contending for the win before finishing third at the mile-and-a-half track.
Chastain wasn't the only Trackhouse driver with a stellar finish last weekend at Phoenix. His teammate Daniel Suárez also finished in the top-10, making it the first time since the team's inception both cars have finished in the top-10.
Last Sunday marked the third consecutive race a Trackhouse Chevrolet has been in contention for a win. Teammate Suárez challenged for the win three weeks ago at Auto Club Speedway in Fontana, California.