On two fresh tires to polesitter Dale Earnhardt Jr.'s four, Johnson held off his Hendrick Motorsports teammate during a 26- lap green-flag run to the finish of the AAA 400 and made a significant dent in the series lead of Matt Kenseth, who finished seventh.
Johnson picked up his fifth victory of the season, his record eighth at the Monster Mile — breaking a tie with Richard Petty and Bobby Allison — and the 65th of his career. The driver of the No. 48 Hendrick Motorsports Chevrolet vaulted over fifthplace finisher Kyle Busch into second in the Chase standings, eight points behind Kenseth.
Johnson also took a moment to enjoy the magnitude of his record-breaking win.
"It's incredible," he said. "To do anything Bobby or Richard has done is quite an accomplishment. We've had a few sneak away from us here, too, over the years. I'm just happy to get that done and be the sole leader of race wins here. It's a very special day."
Johnson held a lead of nearly five seconds when NASCAR called the fourth caution of the race for debris in the form of a spring rubber that had dislodged from a car and landed on the concrete racing surface in Turn 3.
With every lead-lap car short on fuel — with the possible exception of Clint Bowyer's No. 15 Toyota — the yellow presented a welcome opportunity to refuel. Johnson's crew chief, Chad Knaus, opted to change right-side tires only, while Earnhardt's crew chief, Steve Letarte, called for a four-tire change.
Earnhardt restarted fourth on Lap 375 of 400 and quickly rocketed into second place, but couldn't catch the five-time champion.
Joey Logano ran third, followed by Jeff Gordon and Busch, as Chase drivers claimed all top 10 finishing positions for the first time in Chase history.
Earnhardt, whose winless streak reached 48 races, relinquished the race lead during a green-flag pit stop on Lap 119 after missing the entrance to pit road on the previous lap. The snafu cost Earnhardt seven positions and 13 seconds on the track, and though a caution on Lap 164 bunched the field and enabled him to make up lost ground, Earnhardt couldn't mount a challenge to Johnson's dominance after that.
On a later stop, Earnhardt lost time getting to his pit stall when he had to slow behind Mark Martin's Chevrolet. Earnhardt conceded that the issues on pit road, particularly the first one, may have changed the outcome of the race.
"Yeah, if you really look at the race as a whole, they did cost us a little bit, at least the mistake I made missing pit road completely. We had the lead, gave up the lead. Jimmie had the lead and was able to take advantage of that clean air when it counted.
"If I had not given up that track position, had a smart enough race to keep the lead when it counted right at the end, we might have won the race. It would have been hard to get by us, just like it was (hard) to get by Jimmie.
"I think missing the commitment cone was a big factor in us not finishing one spot ahead of where we are. But the other pit stop wasn't that big a deal. I came on pit road about as hard as I could. The 14, Mark, was running maybe five, 10 miles an hour slow in the first couple of (pit road timing) segments. I don't know that cost us a ton of time."
Chase drivers Kurt Busch and Carl Edwards were casualties of bad luck and a broken part, respectively. Busch was caught two laps down after an early green-flag pit stop that preceded the second caution on Lap 164. He finished 21st and dropped to ninth in the standings, 55 points behind Kenseth.
Edwards, who entered the race fourth in points, took his car to the garage on Lap 377 with broken hub, finished 35th and plummeted seven spots to 11th in points, 65 out of the lead.
Kenseth sees points lead shrink
Early on Sunday, Matt Kenseth looked primed to do the unprecedented: win a third consecutive race to open the Chase.
Kenseth's Joe Gibbs Toyota led 36 of the first 167 laps in Sunday's AAA 400 at Dover International Speedway.
And virtually the only time Kenseth was out of the top five was at race's end, when he faded to seventh as Kyle Busch and Kevin Harvick passed him by.
But that was enough to ruin a perfectly fine afternoon for Kenseth, looking to regain the NASCAR title he won in 2003. Kenseth, who entered the race 14 points ahead of Kyle Busch in the Chase standings, left Dover with only an eight-point cushion on five-time champion Jimmie Johnson.
"Overall, for how bad I felt like we struggled with the car, that was a decent finish," Kenseth said. "(But) when you look up, it's everybody that finished in front of you. (They are) all the cars that you're racing for points."
Despite having a top-10 car all day, Kenseth never really felt comfortable with his setup on Sunday.
"We kind of missed it today," he said. "There are times that we've run a lot better than that. I certainly wanted to do better than that."
The final pit stop didn't help. In fact, Kenseth would have preferred that the race stayed green, even if it meant he and the other leaders would need to pit for a splash of fuel in the final laps.
"Jason (crew chief Ratcliff) said nobody who was going to win the race could really make it (on fuel). A lot of those cars that I think were going to try to make it were already a lap down, so I wish it would have (stayed) green to the end. I think that would have got us a top-three or four."
The unfortunate timing of the final caution was compounded by bad luck with the pit strategy on the final stop that sealed the disappointing finish.
"We got caught with being the last on two tires and restarting on the inside, which was really bad," Kenseth said.
As difficult for Kenseth to swallow was losing valuable points off his lead in the Chase was failing to perform up to his expectations at one of his favorite tracks.
Kenseth entered Sunday's race with a driver rating second to only Jimmie Johnson (in the previous 17 races at Dover) and 13 top-five finishes in his previous 29 starts at the mile oval.
"I feel like this is one of our best race tracks and you want to do better than seventh at one of your best tracks," he said. "Overall, it was a solid day, but we wished for a little more."
Kenseth said one silver lining is that he also likes some of the upcoming tracks on the schedule, including Kansas Speedway next week.
"I'm looking forward to getting there," he said.
Earnhardt fails to capitalize on winning opportunity
If not for Hendrick Motorsports teammate Jimmie Johnson and a couple pit road snafus, Dale Earnhardt Jr. would likely have been celebrating his 20th career Sprint Cup victory and a dominant weekend at the Monster Mile.
Instead, Earnhardt settled for a second-place finish in Sunday's AAA 400 at Dover International Speedway, leaving somewhat dejected, but with a positive outlook for the remaining seven races and the knowledge that his equipment is plenty fast enough to get the job done.
"I'm just real disappointed," said Earnhardt, who had earned the pole after finishing sixth the previous week at Loudon, N.H. "We had an awesome car. These are two of the best cars I've had all year.
"It's probably harder to run second than it is fifth or 10th. When you have a car like we had today – and you don't get good cars every week – you like to capitalize. I've got to thank the team. But running second is no better than running 10th. I'd like to get a trophy here, soon."
It's been more than a year and 48 starts since Earnhardt's last trip to Victory Lane, last June 17 at Michigan. His only victory in 28 career Cup starts at Dover came in 2001.
"In the last couple of weeks, we've been able to really show what our team is capable of," Earnhardt said. "We've been really quick on the sheet every day – fast in practice. The changes we're making seem to be working and we're going in the right direction. I feel like when we get it right, we can compete and we can win. We came really close today."
Earnhardt said he had no one to blame but himself for surrendering control of Sunday's race after leading 76 of the first 117 laps.
Attempting to pit under green at that point, he missed the commitment cone to pit lane and was forced to make an extra circuit of the one-mile oval. That miscalculation dropped him from first to eighth, 9.3 seconds behind Johnson.
"I take responsibility for getting a little too eager coming onto pit road for that green flag stop," Earnhardt said. "That track position is really important and I gave that up early in the race with that mistake coming onto pit road. It cost us a shot at the win."
On Lap 313 of 400, Earnhardt again was a bit slow in the pits, losing time behind Mark Martin on entry. Running second at the time, he dropped to fourth.
After a caution flag for debris with 29 laps to go prevented race leaders from requiring splash-and-go pit stops in the closing laps, a potentially game-changing decision by crew chief Steve Letarte gave Earnhardt one more shot at catching Johnson. While Johnson took only right-side tires, Earnhardt's team opted for four.
Earnhardt restarted fourth, but quickly passed teammate Jeff Gordon and Matt Kenseth to provide Johnson's stiffest challenge.
"Junior drove a whale of a race. He kept me honest there at the end," Johnson said.
"Jimmie is so tough here, it's no surprise that he won," said Gordon, who vaulted three places in the standings and trails Kenseth by 39 points. "It was a great job by Junior, too. That was fun to watch."
Just not real fun for the driver who finished second.
"Real proud of the company," said Earnhardt, who has 16 top-10 finishes this season. "(But) we were going to have a helluva party if we could have got to (Johnson). ... I'll be honest with you: It sucks to lose, regardless of who wins."