Tyler Reddick was signed to a full-time schedule for the 2018 Xfinity season, replacing William Byron, who was promoted to the Monster Energy NASCAR Cup Series. On February 17, 2018, Reddick beat teammate Elliott Sadler in a photo finish to win the season-opening race at Daytona. At a margin of .0004 seconds, it is the closest finish in NASCAR history. At the Ford EcoBoost 300, Reddick took advantage of pitting while leader Cole Custer stayed longer than him and won the race while also winning the championship, joining Chase Elliott and William Byron as the third different driver to win the championship and Rookie of the Year honors in the 9 car.