RICHMOND, Va. – Tempers flared Saturday night at Richmond International Raceway after what had been a relatively calm regular season for NASCAR.

Just in time for the Chase for the Sprint Cup playoff, too.

Brad Keselowski angered both Matt Kenseth and Kyle Busch, and Ryan Newman and Tony Stewart – now apparently former friends – clashed on the track, with Newman sounding off with harsh, personal comments.

Keselowski seemed to reignite a feud with Kenseth, who has been occasionally angry at Keselowski and his Team Penske teammate Joey Logano for seemingly two years now.

In October 2014 at Charlotte Motor Speedway, Keselowski and Kenseth clashed on the track, and then Keselowski bumped into Kenseth on the cooldown lap as the cars were returning to pit road. Kenseth had already begun to unbuckle his safety belts and was incensed, so he tracked Keselowski down and tackled him in between haulers as a melee broke out.

Last year, contact between Keselowski and Kenseth at Martinsville Speedway was apparently the final straw in Kenseth’s anger toward Team Penske, and he took revenge on Logano when he returned to the track, intentionally wrecking the No. 22 car while it was leading the race. Kenseth was suspended for two races as a result and Logano’s shot at a title was over.

Kenseth said Saturday that Keselowski “cleaned me out” when the No. 2 car slipped up the track on lap 335.

“It’s all on Brad,” Kenseth said. “I’m sure he’ll send a tweet out or go on a TV show and explain how it wasn’t his fault, but he knows better than that. He knows his angle was bad and he drove way up in the corner because he made a mistake because he was trying to make up for it and had no respect for anybody in the outside lane.”

Keselowski said he didn’t hear Kenseth’s comments, but understood why he was upset.

“Yeah, I just missed a shift and ruined Matt’s day. … I made a mistake, and it was kind of crappy for everyone,” a subdued Keselowski said. “Hopefully, he’ll accept the apology. … That’s not what anybody wants to see, including myself.”

The drivers appeared to speak briefly while waiting to take a group photo of all the Chase contenders after the race.

Additionally, Keselowski also got under Busch’s skin again – something that seemingly happens every week with the two hard-nosed drivers racing around each other.

“I would expect both of us not to be able to stay away from each other, with both of us having really good teams and really good cars and having the capability of winning every week,” Busch told USA TODAY Sports. “There’s no fresh (start) between me and Brad. You’ve just got to focus on what you need to do and what your agenda is, and try to not let anybody else derail that.”

Keselowski, who last year wrote a blog post about his desire to be on better terms with Busch, sounded mildly surprised when told of Busch’s comment about the lack of a clean slate entering the Chase.

“I can only speak for myself and say I don’t feel that way,” Keselowski said. “I wish everyone the best.”

Then there was the crash between Stewart and Newman – who failed to make the Chase and was quite angry about how his night turned out.

Newman said Stewart chopped down on him in the corner in a crash that ended up causing a red flag — an act which Stewart acknowledged but said it was only after repeated contact from Newman.

“I guess he thought he was in a sprint car again and didn’t know how to control his anger,” Newman said.

The comment sounded like a reference to Stewart’s incident with Kevin Ward Jr., where his car struck and killed Ward at a sprint car race in August 2014. Newman said Stewart “should be retired, the way he drives.”

Newman then turned to the NBC Sports Network camera and told fans Stewart was “bipolar” and had anger issues, recommending fans look them up on YouTube.

Later, Stewart somewhat brushed off Newman’s comments when told of the outburst.

“It’s a stressful night for him; he’s trying to make the Chase,” Stewart said. “It’s a stressful moment, so he’s going to say whatever he’s going to say. … He probably doesn’t want to be friends right now. It’s up to him.”

Follow Gluck on Twitter @jeff_gluck