NASCAR Martinsville 2016: Preview, lineup, starting grid for Goody's Fast Relief 500

With a career encompassing six championships and 78 wins, there isn't much Jimmie Johnson hasn't experienced. Point races that go down to the wire, improbable comebacks from apparently dire circumstances, races he should've won but lost and vice versa, unusual parts failures at the most in opportune times.

In other words, Johnson's been there, done that. Many times over.

Yet, the six-time champion finds himself in an unfamiliar situation as the three-race semifinal round of the Chase for the Sprint Cup begins Sunday at Martinsville Speedway (1 p.m. ET, NBCSN). For the first time since NASCAR went to an elimination playoff format in 2014, Johnson finds himself among the eight drivers vying for one of four spots available in the championship finale.

"Gosh, this Chase has such a different feeling than Chases I've won in the past," Johnson said. "I still feel like I have this massive hurdle to get over to get into the Final Four."

"This format just requires such a different mindset and a different way to make it to the Final Four to even have a shot at the championship."

Each of Johnson's six titles came in a format where drivers accumulated points for the duration of the 10-race playoff. So dominant was the No. 48 team, which won a record five consecutive championships from 2006-2010 and another in 2013, that NASCAR drastically overhauled the Chase.

Perhaps because NASCAR "Jimmie proofed" the Chase, or more so because of a lack of execution combined with bad luck, Johnson hasn't enjoyed much success under the multi-round, knockout parameters.

In each of the past two years Johnson came into the Chase projected to make a deep playoff run. Except neither time did reality align with expectations. In 2014, he was bounced in the second round after three successive subpar finishes brought about by circumstances largely out of Johnson's control.

Last year, Johnson's Chase ended even sooner and in far crueler fashion. Sitting second in points heading into the first round elimination at his best track, Dover International Speedway, he seemed a lock to advance.

Not quite. A rear axle seal -- a part estimated at $5 -- broke, relegating Johnson to a crippling 41st-place finish.

Thus far Johnson has escaped any problems during the Chase. The Hendrick Motorsports driver transferred easily out of Round 1, then won the first race of the second segment to guarantee his advancement and the position he currently finds himself. If he can win one of the next three races or rank high enough in points among the title-eligibles without a victory, he'll qualify for the championship finale Nov. 20 at Homestead-Miami Speedway.

Conventional wisdom suggests Johnson is a favorite to make it to Homestead because of how the third round sets up with races at three of his very best tracks. He is an eight-time Martinsville winner, won the past four fall events at Texas Motor Speedway, and his 7.8 average finish at Phoenix International Raceway leads all drivers.

"With this new format I think his Achilles was that second round and by him getting through the second round and being in this round, this is like an excellent opportunity for him," teammate Jeff Gordon said. "I feel very confident they are going to go to Homestead."

Befitting someone who comprehends how rapidly one's fortunes can swing in a format where one bad result can spell doom, Johnson assumes nothing. His mindset is to focus on finishing as well as possible every given week, not of the possibilities ahead.

And if a reminder is needed of what can happen, Johnson just thinks back to Dover last year.

"Stats are cool, but they don't mean what is going to happen in the future," Johnson said. "You just cannot take anything for granted. Sure they are great tracks, sure we expect to be competitive, but if you have a bad race at one of the three, and you don't win, you aren't going to make it. You need to have three clean ones or win."

Goody's Fast Relief 500 lineup