Stenhouse, Buescher and Suarez claimed respective stage victories while Erik Jones claimed the Fan Vote title to transfer from the All-Star Open to All-Star Race.
The 29-year-old Chastain from Alva, Florida, rallied from an early pit road speeding penalty to overtake Erik Jones on the final lap through the tri-oval to claim his second career win in NASCAR's premier series.
The reigning NASCAR Cup Series champion led four times for 28 of 200 laps and fended off the field in a four-lap shootout to claim his second victory at Auto Club Speedway.
The 2012 Cup champion overtook Matt DiBenedetto on the final lap and held off the field to claim his first Cup victory of the 2021 season at the world's fastest venues.
