There were less than 30 laps to go, and Busch thought he had the fastest car.
"With 20 laps to go, I thought we had it in the bag," he said Friday night.
Then Denny Hamlin "came out of nowhere," Busch said, and he had to hold him off in a stirring side-by-side, last-lap duel to win the Nationwide Series race at Richmond International Raceway in a car owned by his younger brother, Kyle.
"I've driven for guys like (Roger) Penske and (Jack) Roush, but when you're driving for a guy named Busch, you've got to be on it, and I was glad to be able to deliver," Kurt Busch said. "It's great to get to Victory Lane as a family."
The victory was the first for Kyle Busch Motorsports in the Nationwide Series, and was Kurt Busch's fourth in the series and first at Richmond.
Kyle Busch greeted his brother before he even climbed from the car, and said it was harder to watch as an owner than to be driving and in control of the outcome.
"This is the most emotional I've ever been for a win," Kyle Busch said. "I'm not sure how we'll run past this, but I don't care. Tonight is the night."
Watching, he said, was harder because Hamlin, his teammate with Joe Gibbs Racing in the Sprint Cup Series, closed in and then pulled inside on the last lap,
Hamlin needed a remarkable surge after a mistake early on. Running third when he headed for pit road at the midpoint of the race, he missed his stall and had to come back around. It dropped him to 24th place, and put him in urgent mode.
"I drove qualifying laps for the last 150 laps and made up a lot of time and was just a few feet short," Hamlin said after losing by less than a hood-length.
He said he considered nudging Busch on the final lap, but considered that it was his Joe Gibbs Racing teammate's team, and buying goodwill might be wiser.
"One of these days, when Kurt's gaining on me and I could use a break at the end, maybe he'll give it to me," Hamlin said.
Harvick, who led 158 laps with a car that seemed the class of the field, especially on fresh tires, faded after the final stops under green and finished third. Ricky Stenhouse Jr. was fourth, followed by Sam Hornish Jr. and points leader Elliott Sadler.
The race also included a bit of history as 70-year-old Morgan Shepherd led four laps when he stayed out under a caution, extending his series record as the oldest to lead a lap.
The race marked the debut of X Games star Travis Pastrana in the series, too, and after starting 25th, he climbed into the top 20 late in the race before getting caught with a speeding penalty on pit road. The pass through penalty hurt, and he dropped to 22nd.
Danica Patrick, who started 16th, was in the mid-20s all night and finished 21st.