Kyle Busch was just trying to maintain the pace behind Martin Truex Jr. while waiting for his chance.
The No. 18 Joe Gibbs Racing team pounced when the yellow flag came out with 21 laps to go at Texas Motor Speedway.
Busch finally regained the lead on pit road during that caution then held on for the final 16 laps after the last restart Saturday night in the Sprint Cup race, completing a NASCAR weekend sweep.
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"As soon as that caution came, my boys stepped up the plate and hit a grand slam," said Busch, who got his 26th career cup win in his 300th start.
After following Truex lap after lap, Busch came off pit road first and charged forward his Toyota forward in a strong restart.
It was the second time this season, and a NASCAR-record seventh time in his career, that Busch won Cup and Nationwide races in the same weekend. He was the polesitter Saturday night, and won the Nationwide race Friday night on the 1½-mile, high-banked track.
Busch, who also won both races at Fontana last month, led eight times for 171 of 334 laps. He is the first driver to win in all three series at Texas, with six Nationwide wins and two in trucks.
"To be in Victory Lane in Texas, there's nothing better," Busch said. "If it wasn't for my pit crew, which is the most awesome group ever. ... Man, those guys were just awesome. They put together a heck of a stop to give us that lead. These cars are amazing to drive. They're fast. They're fun."
Truex was trying to win for the first time since June 2007, but his winless streak reached 210 races when he finished a half-second behind Busch. Truex came into the race 25th in points with no laps led this season, but had his Michael Waltrip Racing Toyota in front for 142 laps at Texas.
"Debris huh????" Truex tweeted about the caution that cost him the lead.
Truex had more than a 4-second lead over Busch soon before pulling in for a green-flag stop on lap 281 just before two cars spun on the backstretch bringing out a caution. Truex had pushed back to a 1.3-second lead just before that last yellow flag that determined the race.
"The last caution came out and we got beat out of the pits, and that was the race," Truex said. 'It was pretty frustrating to run second again."
NASCAR said that during a postrace inspection, it was determined that Truex's No. 56 car was too low in the front. The series said the car would be looked at further, and the issue addressed next week.
Busch has 111 career victories in NASCAR's three top series — 26 in Sprint Cup, 55 in Nationwide and 30 in Camping World Truck.
His weekend sweep in California last month was overshadowed by the last-lap crash in the Cup race between former teammates Denny Hamlin and Joey Logano that left Hamlin with a fractured vertebra in his lower back.
Logano barely made the start of the race after prerace inspections turned up problems. He started at the back of the field, but worked back to a fifth-place finish. Jimmie Johnson maintained his series points lead by finishing sixth, ahead of Aric Almirola.
"It was one of the toughest races I think we've ever dealt with and to come home with a top-five out of something like that, we couldn't be more excited about that," Logano said.
NASCAR confiscated the original rear-end housing parts from Logano's No. 22 Ford and the No. 2 of Penkse Racing teammate Brad Keselowski, the defending Sprint Cup champion. NASCAR officials said the situation will be evaluated further next week, when decisions about any penalties could be made.
Logano gave up his starting spot of 18th after being late to the starting grid while having to get additional inspections. Keselowski got on pit road in time and started 16th, and finished ninth.
In keeping with a long tradition for the winner at Texas, Busch received a cowboy hat and got to fire trophy six-shooters loaded with blanks in Victory Lane.
The title sponsor of the race was the National Rifle Association, which came at a time when the U.S. Senate weighs legislation intended to reduce gun violence in the wake of the December shootings at Sandy Hook Elementary School in Newtown, Conn. A senator from Connecticut requested that the Fox network not broadcast the race.
Busch didn't get a rifle or shotgun for his qualifying run Friday like the other fastest Cup qualifiers had gotten since 2005. But track president Eddie Gossage said Saturday that was because there wasn't a sponsor for that award this year, and not any reason other than that.
Carl Edwards, a three-time winner at Texas who had his seatbelt come loose during the race, finished third ahead of Roush Fenway teammate Greg Biffle.
Brian Vickers, filling in for Hamlin in the No. 11 Gibbs car, finished eighth. Hamlin was at the track this weekend and said he feel good, though he will miss at least another race, maybe more.
A part-time Cup driver for Waltrip's team, Vickers had five top-10 finishes in eight races last year. Vickers is a full-time Nationwide driver for Gibbs
This was the 25th Sprint Cup race at the track that opened in 1997 and started hosting two races a year in 2005. It also was the first night race this season, and the first for NASCAR's new Cup cars.
Kurt Busch started on the front row next to his brother, but finished 37th and 18 laps off the lead.