NASCAR Xfinity Series® rookie Sammy Smith scored his first career victory with a dominating performance in the United Rentals 200 at Phoenix Raceway.Driving the No. 18 Pilot Flying J Toyota GR Supra, the 18-year-old Joe Gibbs Racing driver took the lead for the final time with 52 laps remaining. He then had to withstand challenges on several late-race restarts to take the checkered flag and become the youngest driver to win a NASCAR Xfinity Series® race at Phoenix