He scored a 10th-place finish in the first stage and ran as high as fifth Sunday in a car he never raced before.
Chastain finished two laps down after causing the final caution on a Lap 262 spin, which he judged “unacceptable,” along with his restart performance (“guys kind of ate me alive”) as a substitute for Roush Fenway Racing.
“It’s hard to get out of the car after you have a top-10 car, and you go and run into people and pick the wrong lanes on restarts and then spin it out at the end,” Chastain said. “That’s pretty silly. Just a lot of mistakes on my end and then at the end just overdriving and for one position to be the first car a lap down. That’s unacceptable.”
Chastain had an average running position of 16.87 over the 400-mile race, which went south after he pitted under green from 15th on Lap 217 of 267. The yellow flag flew five laps later, and Chastain took a wavearound to restart 21st.
On the restart, he made contact with Kurt Busch and pitted under green to fix a tire rub, which left him a lap down when he spun with five laps remaining.
“There were a lot of small mistakes on my end, but I learned a ton,” he said. “The car deserved a lot better finish. Obviously, we showed that early and I just didn’t have great restarts. I just have to be better.
“RFR and everybody puts so much into these cars, and ultimately I’m the one holding the wheel. We had such a good first stage and had so much confidence and from there I just started making mistakes.”
Chastain, who finished 10th in Sunday night’s rain-delayed Xfinity race, will be driving the No. 6 for Roush while Newman recovers from his Daytona 500 crash. In a statement from the team Sunday morning, Newman indicated he plans to drive again this season, but no timetable has been provided for his return.