Reigning champion Jimmie Johnson and Kurt Busch had another ill-tempered confrontation on the track at Richmond, although it was afterwards that the fireworks really started, especially for Busch.

The on-track conflict started on lap 186 of 400, when Busch locked up and slid into Johnson into turn 1, sending the #48 into the outside wall giving him heavy damage to the rear of the car.

Johnson's race was already compromised and so he targeted the next best thing - wrecking Busch's night as well. He dove down into the corner underneath the #22 and spun Busch on lap 247. Busch got off lightly and was able to resume - he finished in fifth place at the end of the night - while Johnson also spun as a result of the contact and ended up in the garage for the next 34 laps for repairs.

"He has no one to be upset with except himself. If he didn't run me over going into turn one, nothing would have happened," said an unrepentant Johnson. "It's simple stuff, you wreck me and I'm going to wreck you."

"When he came back to us, you could see it coming," Busch said, who also called Johnson a "five-time chump" as he fumed after the race. "He's been able to beat guys the last five years just by outdriving them with what he has for equipment. If he wants to switch equipment, lets see what we can do but I'm going to beat him fair and square with my Penske Dodge."

And it was at this point that things got really strange.

In a live televised pit road interview, Busch maintained his earlier line from their clash at Pocono that Johnson's hostile reactions showed that Busch was rattling the champion: "That's not something you see from Jimmie Johnson every day so I know we're in his head. If we're going to race this way, he's got to worry that there's ten other guys in this Chase, not just the #22."

In the formal press conference after the race, when Johnson was asked about Busch's "in his head" comment, Busch interrupted to flatly denied he'd said it: "I didn't say that tonight. Did not." One Associated Press reporter then showed him the transcript of the earlier TV interview, which Busch snatched out of her hands, ripped in half and threw both pieces back on the reporter's desk before storming out.

Earlier, Busch had been approached in the pit lane by reporter Joe Menzer, who had started to ask, "Kurt, can either you or Jimmie win the Chase ..." before Busch had suddenly cut him off.

"How did I see you were going to come with that? We're good," Busch had snapped before turning away and walking off. Menzer called after him that it was a valid question given the on-track incidents, at which point Busch reportedly rounded on him, started swearing at Menzer and was apparently only prevented from getting physical with the reporter by the intervention of Penske Racing team members.

Menzer had later been present at the subsequent formal post-midnight press conference when Busch arrived for that, and the driver approached the reporter again for a conversation that soon grew heated and loud once more. The situation almost again looked on the verge of getting physical before Busch was called to the front of the room to take part in the conference with Kyle Busch, Ryan Newman, Tony Stewart - and Jimmie Johnson, who deliberately took a seat as far down the other end of the table as possible.

"He can keep talking. He can keep running that mouth. He can't help but run his mouth," summarised Johnson. "Hell, he threatened to fight's Joe. Interesting stuff." He may as well have added, who is in whose head now?

The two did at least have a few quiet words as the 12 Chase contenders were gathered for a photo-call before the end of the long night: "We spoke a few minutes up on the stage, and I certainly hope it's behind us," said Johnson. "I have no intentions to run people over."

Busch also insisted that he wanted this over and done with. "This is where we stand. Cars have been racing; cars have been wrecked. We have a Chase to start, so let's forgive."

Everyone agreed that this had been one of the most all-round tense press conferences they could remember, lightened only by flashes of comparative surrealism. Perhaps it was the late hour, or the strain of the exhausting 400 lap night race, or the euphoria and release of stress after the Chase positions were finally decided.

How else to explain Carl Edwards and Brad Keselowski's weird sidebar discussion about crayons and little sharpeners, after Keselowski compared making the Chase to being "like a one-year-old that got his first box of crayons: happy and amazed to have them"?

Or how - when Edwards was asked a serious question about why he had stayed out and decided not to pit under one of the later cautions - Keselowski couldn't resist turning around and chipping in: "Yeah, Carl. Why didn't you?" which was greeted by a cheerful "Screw you, Brad!" by Edwards.

Or Matt Kenseth arriving to find no seats available at the drivers' table, only to briefly take up residence on Jimmie Johnson's knee?

By this point a high degree of black humour was settling in on the room. When Kenseth challenged another reporter's question about his not having had any top four finishes all season, the reporter held up his notebook and asked if Kenseth would like to rip it up instead, which got a smile from Kenseth and a strained laugh from the room.

"Thank you, guys," deadpanned Kenseth as the most bizarre NASCAR press conference in living memory finally broke up. "You're doing a fine job."