Although Busch won the pole Friday, he was forced to start in the back after his team replaced the motor in the No.18 Joe Gibbs Racing Toyota.

Busch led two laps in the early going when teams pitted under green. He took command in the late stages when he passed Jeff Burton on lap 227. Busch gave up the top spot during a late round of stops, but grabbed it for the final time when he moved ahead of Bowyer with 17 laps to go.

"This is pretty cool," Busch said. "I didn't know exactly what it would mean. Coming to the checkered flag, there were knots in my stomach. This is probably as big as the Daytona 500. I said it wasn't going to be, but it is."

After patiently making his way through the field for the most of the race, Busch had to hold off the leaders on two late-race restarts. When he grabbed the lead from Bowyer, Paul Menard made contact with Greg Biffle and smacked the wall on lap 270. Then Jimmie Johnson got loose and spun with the back end of his car making contact with the wall 10 laps later. The 14th caution, a new track record, set up the three-lap shootout to the finish.

"The last 25, 30 laps, I was just as nervous as could be, Busch said. "Wasn't really all that great at hitting my marks. I was hitting them good enough, I guess. Fortunately we ran that many caution laps there at the end. That helped, too."

The victory was Busch's 13th in his Sprint Cup Series career and the first for JGR at Las Vegas.

Bowyer finished second, followed by Burton, David Reutimann, and Bobby Labonte.

"It feels like a win almost," Bowyer said. "(We) went a lap down, got real loose early, got that lap back, got run into on a restart, 15 wide, whatever we were, fixed that, got going back again."

While Busch and fellow Toyota drivers David Reutimann, Marcos Ambrose, Brian Vickers and Scott Speed made engine changes earlier in the weekend, Roush Fenway Racing experienced most of engine woes with their Fords in the 427-mile race.

On the seventh lap, Matt Kenseth's bid to become the first driver to win the first three NASCAR Cup Series races of the season quickly went up in smoke when he blew an engine. Kenseth began experiencing engine trouble during the first caution when his motor shut off.

"I think it's the first failure we've had in over three years," Kenseth said. "It's just unfortunate we didn't get to race."

Kenseth, who won at Daytona and California, finished 43rd at Las Vegas.

David Ragan, also from the Roush camp, had his day end early when his engine expired on lap 74.

"When your pushing the issue and trying to get all the power out of it, you're going to have things like this happen," Ragan said.

Mark Martin was running in the top-five on lap 122, but a blown engine forced the veteran driver out of the event.

"It was a very encouraging run, but very disappointing," Martin said.

Martin, who suffered engine failure for the second straight week, ended up with a 40th-place finish.

Two separate wrecks occurred just before the half-way point with Reed Sorenson slamming into the wall on lap 138, and Aric Almirola spinning and making contact with the wall on lap 144. Kasey Kahne and David Reutimann spun while trying to avoid Almirola.

Michael Waltrip and Denny Hamlin also got loose and made contact with the wall during the mid-stages.

During a round of green-flag pit stops, Gordon overshot the entrance to pit road on lap 219. He blew a tire on the following lap. Gordon had to make several stops during the caution to repair his right-front panel caused by the blown tire. He rebounded for a sixth-place finish.

Biffle, Vickers, Jamie McMurray and Dale Earnhardt Jr. completed the top-10.

Gordon, the four-time Cup Series champion, moved atop the point standings. He holds an 18-point advantage over Bowyer. Kenseth dropped from first to third, trailing Gordon by 40 markers. With the victory, Busch moved up to sixth in points (-54).

The series heads to Atlanta Motor Speedway for next Sunday's Kobalt Tools 500.