And then on lap 363 came the wreck that everyone would still be talking about the morning after. Kevin Harvick was moving up on Kyle Busch when the #18 seemed to struggle off the turn and lose a little momentum; the two rubbed alongside each other before Kyle pulled out in front, and Harvick gave the back of the #18 a tap but both cars were able to absorb the impact. It did give Clint Bowyer an opportunity to dive down the inside of the two as they slowed up, and they were three-wide out off the turn with Harvick in the middle and Busch on the outside.
The three compressed as they came out of the turn, and Harvick in the middle ran out of room. First he hit Busch - who was right up against the wall and bounced toward it, destabilising Harvick who shook left and hit Bowyer on the inside instead. And Bowyer got by far the worst of it, sent sheering off at right angles to make a nasty, hard head-on impact with the inside wall that crunched up the nose in a big way and made sure he would play no part in the restart.
"It was tight racing after the restart there and Harvick was up on the top, a little bit loose, and I gave him room," claimed Busch afterwards. "He kind of came off the wall - that's a bad angle, obviously - and then lifted early to let me go into turn 3 and I thought it was all good. Then he drives into the back of me there, so ... it made my car loose all the way through the exit, and just made a run for those two guys to get back on my inside.
"And then obviously Clint wrecked, bouncing off Harvick. It was just uncalled-for; it was unacceptable racing. I know it's the last couple of laps, but I gave him room coming off 2 and I didn't get the room."
And the incident was not done just because the caution was out: Busch moved down off the wall as they proceeding down the straight, and tagged the back of the #29 sending Harvick for a spin. Both cars would need to take to pit lane, but while Busch went on to finish in 11th the additional spin had sent Harvick all the way down to 17th, and he was steamed up about it.
After all that, there was still a race to resolve - Regan Smith led Carl Edwards to the green-and-chequered flag on lap 368, getting a good start thanks to a boost from Brad Keselowski; but he was unable to pull away from the #99 who was right on his tail and threatening to deny him that all-important first career win. On the final lap, Smith was pushing so hard that his rear end stepped out and he scrapped the wall out of turn 2, but he gathered it up and didn't give Edwards any chance to react by diving down to the inside line. The moment of danger had passed for the #78: the chequered flag - and the win - was finally his.
"I can't believe it, you guys," Smith said over the radio. "This is the Southern 500. We're not supposed to win this thing. As well as Smith's frst series win, it's also a first victory for his team and for owner Barney Visser. "I don't really know how to put it in words right now. It is so surreal," Smith added.
"There's been a lot of times when they could have gotten down on me last year [or] this year, and everybody stuck behind me and gave me the support I needed to keep my head on straight. I'll be honest with you, when I walked to the car tonight, I literally thought we could win the race. I think that every week when I walk to the car. The difference is, this week we did."
But there were shenanigans brewing elsewhere over that lap 363 accident: Harvick was blatantly tracking Kyle Busch around the cool-down lap, so that the #18 even opted to overshoot the entrance to pit lane in a bid to avoid the attentions of the #29. Harvick wasn't about to let him get away with that and continued to stalk Busch, the two of them briefly coming to a stop before Busch then made a move to circle back to the pit lane entry.
Harvick got in first, the damaged car of Bobby Labonte briefly trapped in the middle of this stand-off before Harvick allowed it through. Then Harvick stopped to block the #18 getting further down pit lane, jumped out of his car and stormed over to Busch's driver-side window and appeared to aim a punch through it, at which point Busch reacted by flooring the accelerator - and pushed the driverless #29 ahead of him around, sending it skewing into the pit wall. Fortunately no one was in the way when he did, and Kyle exited to the garage area while the altercation spilled out and seized the two drivers' respective teams, Joe Gibbs Racing and Richard Childress Racing - ironically situated side-by-side on pit lane, and thus having to be physically separated by a NASCAR peacekeeping task-force as harsh words turned to physical shoves between them.