One quarter of the Coca-Cola 600 is down and Denny Hamlin's No. 11 Toyota is out front, ahead of five-time defending series champion Jimmie Johnson, Roush-Fenway Racing teammates Matt Kenseth and Carl Edwards, and Dale Earnhardt Jr round out the top-five.
The race is under yellow for the second time for a spin by 2000 Cup champion Bobby Labonte.
Edwards has led the most laps, but lost the lead on a cycle of pit stops after the first caution. Jeff Burton, who took two tires, led at the restart but steadilly dropepd through the field, while Hamlin asserted himself at the front. Johnson had begun to run Hamlin down at the time of Labonte's spin.
Greg Biffle, another of the Roush-Fenway Racing armada, has had issues with his cool-box, a major malady on a 90-degree night. David Stremme, who fell out of the race early, is on standby to take over for Biffle should he need to step out of the car due to the heat.