Jimmy Johnson had taken the lead and was pulling away when the caution came out seven laps from the end of the LifeLock.com 400 late Saturday.
After the restart, Busch was able to catch Johnson and they raced side-by-side until Busch passed on the outside with a lap and a half to go.
"That pass for the lead there, I got a good restart on Jimmie and was able to push him a little bit on that start," Busch said.
"I got him going, and then had to go to the outside, because I knew he was going to go to the bottom there through one and two. It stuck and we were able to get by him there."
Busch had started on the pole and led 165 of the 267 laps.
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