In deep trouble after a disastrous early retirement at Chicagoland and a tepid mid-field outing at New Hampshire, reigning NASCAR Sprint Cup champion Kevin Harvick looked set to fall at the first hurdle in this year's championship play-offs. He was so far behind in the points coming into this weekend's race that only a flat-out win could save his hopes of staying in with any chance of retaining the title in 2015.

So that was precisely what Harvick immediately set out to do, taking the lead from pole sitter Matt Kenseth as early as lap 24 after which it was clear that there would be no stopping him - short of another hurricane hitting Dover International Speedway before the chequered flag came out.

CLICK: Full NASCAR Sprint Cup Series race results from Dover International Speedway.

In the event, the Stewart-Haas Racing #4 led for a whopping 355 laps which is more than Harvick has ever been out in front for in a single race in all his 15 years of competing at NASCAR's top level. There were a few nervous moments when it seemed he might be on the edge in terms of fuel, but a late caution for Front Row Motorsports' Brett Moffitt spinning out enabled him to take care of that. Even the decision to go for two tyres in that final round of stops where most of his rivals went for a full set of four proved not to adversely affect his momentum, and by the end of the 400-lap race he had clinched his third win of the year and his 31st victory in 531 Cup starts in total. It's the first time he's won at Dover in 30 outings here. Most importantly of all, it meant he stayed in the Chase: his Hail Mary had paid off handsomely, better than even he could surely have dared hope.

"I'm just so proud of everybody from Stewart-Haas Racing to do everything that we've done the last three weeks, really," Harvick said afterwards. "Obviously, we weren't in a great position coming it to today. That's what these guys are made of and that's what teamwork is all about.

"I've just got to thank everybody from Budweiser, and Jimmy John's and Chevrolet - it's the 750th win for them," he added. "This is what it's all about, those big time moments."

Harvick's victory means he automatically progresses to the second round of the Chase regardless of the points standings; and that had major ramifications for the rest of the field battling to stay in, with the bottom four drivers in the points without a win left battling for survival.

After his early wreck at New Hampshire, Joe Gibbs Racing's Kyle Busch was one of those who came into the weekend in the drop zone, at risk of undoing all that hard work in the regular season that had seen him make it into the initial Chase line-up despite missing the first 11 races of the year due to injury. Like Harvick, Busch knew that he absolutely had to have a strong finish this week, although his points situation wasn't as severe as Harvick's so second place would do at a pinch. Sure enough, that was where Busch quickly worked his way up to and then spent the majority of the race running. He was 2.639s behind Harvick when the race reached full distance.

"We had a second-place car and we finished second with it. Nothing to hang our heads about there," said Busch. "I can't say enough about my team; these guys did an awesome job. They prepared a great race car for me and gave me the piece that I needed in order to go out there and perform and run like we did today.

"We just have to get a little bit better or actually a lot better to catch that #4 car [but] the things that we needed to do today we did. The first 300 laps it seemed pretty simple and then the last 100 laps it got a little crazy with tyre strategies and restarts and things kind of going on and trying to figure out who and how hard you had to race people and people wanting to race you real hard even though they're just racing for the best finish they can get.

"Fortunately we came out with that finish and second-place was what we needed to do," he added.

With both Harvick and Busch out of danger of elimination, the situation was growing increasingly desperate for those still under threat at the lower end of the points. After his penalty for unapproved parts at Chicagoland, Michael Waltrip Racing's Clint Bowyer could only have progressed with a win and there was never any hint that would happen; similarly Richard Childress Racing's Paul Menard never threatened to claw his way out of the drop zone either. That left two more drivers to be decided for early elimination to be decided.

The fiercest battle was between Hendrick Motorsports' Dale Earnhart Jr. and Ganassi's Jamie McMurray, who came into the race so close on points that the mathematical situation between them was simple: whoever crossed the line first would progress, while the slower one would be out. Their race-long battle drove the pair up through the running order until they were running up in third and fourth positions, and when the chequered flag came out Earnhardt had done just enough and was almost two seconds clear of Ganassi and safe from Chase elimination thanks to a tie breaker, as the pair finished tied on points. That was despite a late scare for Earnhardt with a loose wheel that would have sealed his fate if not for a conveniently timed caution for Moffit's spin on lap 354 which enabled the #88 to have the wheel taken care of during the final round of mass pit stops under yellow.

"A real good day for us. The car did everything we needed," said Earnhardt. "I hate some guys don't get to make it and some guys do, but I'm glad we are able to move on to the next round. It kind of resets and hopefully we don't make any more mistakes and make it too hard on ourselves to try to get to that next round."

"We were driving so hard those last few laps and it's just hard to make up any ground," sighed McMurray, so close to making it through. "It's frustrating that we weren't able to make it to the next round, but it was a good day for the Nature Made car. We just needed one more point."

Earnhardt's knife-edge success meant McMurray joined Menard and Bowyer on the way out of the Chase. But the biggest shock was still to come: the driver who has been the undisputed master of the Chase in the last decade and who came into Dover seemingly without any serious concerns about progressing to the second round was about to suffer a monumental fail.

In his 500th NASCAR Sprint Cup outing, Jimmie Johnson's day was going according to plan until the first round of pit stops under a competition caution on lap 40, whereupon both he and Denny Hamlin were handed speeding penalties and sent to the back. For Hamlin this was no major concern as his win at Chicagoland had already assured the JGR driver safe passage to the next stage of the Chase; and it didn't seem such a huge hurdle for Johnson either, the Hendrick Motorsport #48 soon working its way smoothly back through the running order with no heroics required as a safe mid-field finish would be more than enough to secure his progression.

By lap 96 Johnson was back up to 16th place; and then the forward momentum ceased when the car developed a serious problem ten laps later. Johnson was forced to come down pit lane under green and take the car to the garage for a rear axle seal issue. Even with a debris caution slowing things up out on the track in the meantime, Johnson was still 36 laps down by the time repairs had been completed and he was able to return to the track. With no hope of being able to get all that lost ground back all he could do was hope that other drivers ahead of him up the road - particularly the key Chase contenders - hit problems of their own and dropped out to allow him to gain a few positions and make up some of those essential lost points that would keep him in the play-offs. Unfortunately for the six-time former champion those retirements were few and far between: other that Moffit, only Jeb Burton crashed out and retired from the race in time to boost Johnson's situation. Worse still for Johnson, neither were Chase contenders; and so when the chequered flag came out the grim truth duly dawned on Johnson and his long time crew chief Chad Knaus that their 2015 Chase campaign had crashed and burned before it had even got a chance to really get off the ground in the first place.

"Definitely disappointed," Johnson said. "It's racing, I've had mechanicals take me out of championships growing up that led to some success for myself and I'm sure helped me with a championship or two. It's just part of racing. It just shows how critical everything is on a race team, and how important every component is and you can't take anything for granted.

"Heartbreaking for sure, but I don't know what else we can do about it we just have to go on and try to win races and close out the season strong."

With the four drivers to be cut from the play-offs now decided, the rest of the Chase contenders could breath easy and just concentrate on finishing the afternoon without any dramas. JGR's Matt Kenseth - already through courtesy of his win last week at New Hampshire - finished in seventh place after trying the cheeky but unsuccessful late gambit of deciding to stay out during the last round of pit stops to see if he could do anything to derail Harvick's run to victory lane.

"It was a challenge, a very big challenge," said Kenseth of his day. "Once the track got a little rubber on it we just lost a hold of the track and kept losing track position little by little as well. Just couldn't get going anywhere."

Penske's Joey Logano finished in tenth place just ahead of Furniture Row Racing's Martin Truex Jr. whose day had got off to a dramatic start when he was sent to the back of the field before the green flag after NASCAR penalised him for unapproved adjustments to the #78. That meant Truex was very nearly in the wrong place at the wrong time when Jeb Burton and Josh Wise made contact in turn 1 and spun on lap 4, nearly collecting Truex in the process. Having escaped that potential disaster Truex was then able to work his way slowly back toward the front of field where he eventually settled for 11th place at the line.

"Yeah we had to start last. It is what it is," said Truex. "We moved on, we did what we had to do. It wasn't a great day for us. It wasn't a great weekend. We have been just struggling trying to get the thing turning. All-in-all we had good speed when we would get track position. We would lose track position and being in long lines on the restarts then we couldn't really go anywhere. It was really difficult to pass today. We had good speed out front, top five speed and then just never really could get back there once we got back in traffic."

Unlike his Hendrick team mates, Jeff Gordon had a fairly calm day of it as he picked up 12th place and a safe berth in the next round of the Chase. Bowyer finished in 14th, now out of the Chase and doubtless already having set aside any thoughts of this year's season and looking forward instead to 2016 and a move to HScott Motorsport before taking over the #14 car from Tony Stewart in 2017.

JGR's Carl Edwards had started from third place on the grid, but minor pit road contact with SHR's Kurt Busch and later concerns about his engine and a tyre vibration had seen him decline to 15th place, which was still more than good enough to keep him in the Chase. Penske's Brad Keselowski crossed the line just behind him in 16th followed by Kurt Busch, Denny Hamlin and RCR's Ryan Newman all making it into the next round of the title battle, while Menard finished in 25th and Johnson was shown in 41st place as both were cut from contention.

It had certainly been a tense, edge-of-the-seat afternoon with the drivers all being given real-time updates about the points standings and having to adjust accordingly. What could have otherwise been a rather routine if not outright dull race given Harvick's level of complete domination all afternoon had been made something of a highlight in terms of gripping intensity.

Now the drivers can allow themselves a relative breather as they goes into the next stage of three races at Charlotte Motor Speedway, Kansas Speedway and Talladega Superspeedway during the rest of October. It's only when the field gets to Talladega that the all-or-nothing thrills will return when another four drivers face the chop; but in the meantime at least one driver can buy themselves peace of mind if they're able to win next weekend's Bank of America 500 and guarantee themselves early immunity from eviction.

Full race results and updated Sprint Cup Championship standings.

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