The 41-year-old Allmendinger from Los Gatos, California, led a race-high 28 of 46-scheduled laps and fended off William Byron during a 14-lap dash to the finish to notch a second consecutive Xfinity victory in Austin.
The 18-year-old Smith from Johnston, Iowa, led a race-high 92 of 200-scheduled laps and fended off teammate Ryan Truex en route to his first Xfinity career win in his 13th series start.
The reigning NASCAR Cup Series champion dodged an on-track incident involving teammate Byron and Gibbs to lead the final five laps and grab his first Xfinity victory in four years.
The 24-year-old Custer from Ladera Ranch, California, will achieve a significant milestone start in his third full-time season in NASCAR's premier series.
The 19-year-old Gibbs from Charlotte, North Carolina, led five of 48 over-scheduled laps as he executed a bold final lap pass on Larson for his eighth Xfinity career victory.
The two-time Cup champion from Las Vegas, Nevada, benefitted from a final lap collision involving Tyler Reddick and Chase Briscoe to become the ninth different competitor to reach 60 victories in NASCAR's premier series.
The Ladera Ranch, California, native rallied from two slow pit stops and through three overtime restarts to claim a dominant victory in NASCAR's return at Auto Club Speedway.
