A radio exchange between NASCAR Cup Series driver William Byron and his crew chief, Rudy Fugle, surfaced on X, thanks to Jeff Gluck of The Athletic, who reported it a few hours ago. No Hendrick Motorsports driver finished inside the top-15 in Sunday’s (August 31) race, the Cook Out Southern 500 at Darlington Raceway.Byron’s teammate, Chase Elliott, who happened to be the highest finisher among the Hendrick Motorsports camp, could only salvage a P17 finish. Kyle Larson fell back to 19th, Byron ended up 21st, and Alex Bowman, who qualified for the playoffs just last week, wound up 31st. Bowman is the only driver from the Hendrick Motorsports camp who made the postseason on points.According to Gluck’s post on X, Fugle told Byron:“We're embarrassed. We've got to execute a lot better all around. Nothing comfortable. We didn't do shit today. We've got to improve and get better and race our ass off every week or it's going to be a long offseason."Byron agreed. Despite being the regular season champion, the Chevy star dropped to fifth in the Championship Standings with a 25-point buffer. Currently sitting in third place, Larson has also lost positions. That being said, the Elk Grove native still has a 38-point cushion above the cutoff line."Yeah, 10-4. That was terrible,” Byron agreed.Well, William Byron still has a head start before next week’s playoff race at World Wide Technology Raceway. Scheduled for Sunday, September 7, fans can watch the event live on USA, with radio updates on MRN or SiriusXM NASCAR Radio.So far, William Byron has made only three starts at World Wide Technology Raceway. Last year, he finished 24th at the racetrack. Joe Gibbs Racing driver Chase Briscoe is the defending winner of the event.William Byron sends a message to Chris Buescher’s spotter: “F*****g wake up!”While navigating through the practice laps at the Gateway, William Byron came face-to-face with an unexpected hurdle. It was the No. 17 of his fellow Cup Series regular, Chris Buescher.While exiting through Turn 2, William Byron followed Josh Berry and Chris Buescher out of pit road. Berry’s car was not an issue at the time, but Buescher started riding the high line, blocking the course of the No. 24 Chevy.“Holy sh*t," William Byron exclaimed on his team radio. “That was like 800 pounds of brake pressure not to fu****g wreck everybody back there. Tell Herm (Buescher’s spotter Mike Herman Jr.) to fu****g wake up."William Byron is in his eighth full season with Hendrick Motorsports in the NASCAR Cup Series. He is currently under a four-year deal with Hendrick Motorsports, which will keep him behind the wheel of the No. 24 Chevrolet Camaro ZL1 through the 2029 NASCAR Cup Series season.