In the Cup race, Kyle took the green flag in the late day sunshine alongside Juan Montoya, but it was his brother Kurt who got the best drive off the final corner to break through and run alongside the #18 , finally getting a nose in front to officially lead the first lap, the two running side-by-side and exchanging the lead through a lap for the next several minutes before Kurt finally got past and put some clean air in between him and Kyle, the two of them pulling out a comfortable lead over the rest of the field.
Because of the recent rain, NASCAR had already announced a competition caution for lap 30 for the teams to check over how the cars were faring, and Kasey Kahne led at the restart only to get trounced by Kyle Busch who was once again the king of the restarts, with Kurt soon up to second but over 2s behind Kyle as the field embarked on a green flag stint that would last 111 laps and which would see over half the 43-car field go a lap down.
There was little change in the top six which saw Kahne, Johnson, Edwards and Keselowski playing back up roles to the Busch brothers in the top six. Green flag pit stops started around lap 80 (save for Marcos Ambrose who needed to pit earlier after a miscommunication with his team in the earlier stop) and Kyle Busch cycled back to the front once they were complete. Brian Vickers got a speeding drive-thru penalty, Dave Penalty needed to come back in for a missing lugnut, Kahne was complaining of a mystery vibration that the team couldn't trace and told him simply to deal with it, and Jimmie Johnson was back to his perennial chronic problem of slow stops.
With little to report on track other than David Reutimann cracking the top five and Denny Hamlin impressing by getting within sight of the top ten having started from the rear because of that overnight engine change, it was almost a relief when green flag pit stops loomed once more, starting on lap 120 with Kasey Kahne but not seeing leader Kyle Busch hit pit road for another nine laps, after which he resumed in the lead with nearly 9s lead over Carl Edwards now in second.
With the darkness now well set in and track conditions changing fast, the second yellow of the night - and the first "proper" caution - came out on lap 139 for debris. While most cars took the chance to come into pit lane, Brad Keselowski and Tony Stewart opted to stay out and assumed first and second position for the restart ahead of Kyle and Kurt Busch and Kasey Kahne in fifth.
This green flag lasted only six laps before another caution, this time for oil on the track after David Ragan was seen skidding at a very wild angle and lucky to save the #6 from a wreck. A few cars opted to take the latest opportunity to pit, including Kahne who still needed that vibration taking care of, but the leaders as a whole stayed out on track and in the restart on lap 158 there was a three-wide battle between Tony Stewart, Kyle Busch and Brad Keselowski for the lead before Keselowski finally stamped his authority on the matter.
Not that it was all going so well for Keselowski: he was suffering from radio problems, receiving nothing from pit lanes and only intermittently able to talk with his spotter, forcing him to rely on using old school hand signals to relay information to his pit chief Paul Wolfe about whether the car needed adjustments for understeer of oversteer at the next pit stop. Keselowski was also forced to keep track of fuel mileage and make his own call on when he needed to come into the pits, and to his credit pulled this all off with aplomb.
Having gone off-sync in their previous pit stops, Stewart was in on lap 180 and Keselowski on lap 187, while Kyle Busch was able to stay out with the main field until lap 193. Dale Earnhardt Jr. and Denny Hamlin had just come into the pits - handing the lead temporarily to David Ragan - when Jamie McMurray's #1 car suddenly suffered an engine failure on lap 200 and expired in a trail of smoke, triggering the fourth yellow of the evening which allowed Ragan to come in for a more leisurely yellow flag stop, rejoining in tenth place.
Keselowski resumed in the lead ahead of Kyle Busch, Jimmie Johnson and Tony Stewart when the green flag came out again on lap 210, but all the leaders would have to pit for one last splash and dash before the end of the race.
Still off-sync, Stewart was the first of those to take to pit road under green on lap 233, surprising many by opting to elongate his stop by taking four tyres where others were set to gamble on taking only two. It was a callback to the traditional approach of using the fresh rubber to stream back up through the field to recover any places lost because of the longer stop, but the changes to cars and tyres this year have repeatedly demonstrated that this tactic no longer works on medium-length "cookie-cutter" ovals such as this and that track position is far more evaluable than fresh tyres - and it was no different here at Kentucky. Stewart would pay for that call by crew chief Darian Grubb and would finish in 12th place, although Stewart himself put the blame down to the #14's pace at restarts: "We just couldn't get going on the restarts," he said. "Beyond frustrating."