Members of Kyle Busch’s camp are used to fans venting their frustrations about his behavior around the track. But when rival drivers do the same, a line apparently is crossed.

If Brad Keselowski didn’t know that before, he sure does now.

Keselowski, who drives the No. 2 Team Penske Ford, took to Twitter on Monday to condemn Busch, who drives the No. 18 Joe Gibbs Racing Toyota, for throwing a temper tantrum after finishing P2 in Sunday’s Coca-Cola 600. And although Keselowski seemed to know he overstepped his boundaries, the comments still didn’t sit well with Andy Graves, vice president and technical director at Toyota Racing Development.

Graves came out swinging, but Keselowski stood his ground.

Given the intense rivalry between these two drivers, as well as the one between Ford and Toyota, this bad blood could boil over at any point. After all, Busch already has traded blows with one Team Penske driver this season.

Thumbnail photo via Michael Shroyer/USA TODAY Sports Images