top-five at Iowa and two top tens as well as finishing 13th in points, the highest of the non-playoff drivers. He achieved this after a tight points battle with J. J. Yeley for the spot in the last four races of the season. In the second half of the season, Chastain rarely finished outside the top twenty and mainly finished in the mid-teens. The season was marred by two fights with fellow Xfinity drivers, one with Jeremy Clements at Bristol after Clements confronted him and one with Brendan Gaughan at Texas after heated on-track competition. Chastain, Gaughan, and crew members from both teams brawled behind Victory Lane after the night race. A crew member from JD Motorsports teammate Garrett Smithley was taken to the hospital with a head injury after the fight. Chastain blamed the confrontation on Gaughan, saying the Richard Childress Racing driver attacked him, but also acknowledged that he races hard and does not play favorites. Gaughan initially avoided discussing the incident with reporters but later boasted about the incident on SiriusXM NASCAR Radio and said that he received several text messages from fellow drivers who were happy about the incident. He did admit that he could've handled the situation later but didn't care about it. That opinion was likely influenced by the fact that 2017 was Gaughan's final Xfinity season, as any retaliation would have to happen within the next two races. In 2017, Chastain joined Premium Motorsports' No. 15 car for his Monster Energy NASCAR Cup Series debut in the AAA 400 Drive for Autism at Dover, an opportunity he initially resisted after being informed of the opportunity by Xfinity team owner Johnny Davis. he finished 20th. Chastain heard from various sources that his driving style made multiple drivers mad on-track, but Chastain says it doesn't bother him. He also drove the No. 15 at the fall Dover race, finishing 38th. Chastain was originally on the entry list to drive the No. 7 car, the second car for Premium Motorsports, at the Cup series season finale at Homestead, but the team withdrew. 2018 In late September 2017, Chastain announced that he would return to JD Motorsports for a fourth year, running the entire 2018 NASCAR Xfinity Series season, as well as hinting at another part-time Cup schedule with Premium Motorsports. He started off the Xfinity season with a top-ten at Daytona International Speedway, and ran his