Two drivers left to battle for title

Editor's note: An explanation of Ricky's "Rule of 72" can be found here.

And then there were two.

In second place in the Chase for the Sprint Cup Championship sits the No. 48 Chevrolet of Jimmie Johnson, the five-time champion. He goes to Homestead-Miami Speedway with a wealth of knowledge, wisdom and experience in battling for titles.

But Johnson faces a tall hurdle in the form of a 20-point deficit, trailing the No. 2 Dodge of Brad Keselowski, a driver on the cusp of winning his first Sprint Cup title in his third full season of racing in NASCAR's top series.

A few weeks ago, as drivers were being eliminated one after another under the Rule of 72, I said that as impressive as Keselowski's run had been, it didn't appear at the time as though his attempt to topple Johnson would end any differently than it did for the other five drivers who tried and failed: Denny Hamlin, Carl Edwards, Jeff Gordon, Mark Martin and Matt Kenseth.

It appeared that only a mechanical failure or a factor the No. 48 team could not control would stop Johnson from cruising to his sixth title in seven years. But that's exactly what happened. A blown tire led to a crash, green-flag-lap repairs in the garage and a 32nd-place finish amid the chaos in Phoenix -- resulting in a 27-point swing in the wrong direction.

As I sit here today with one race to go, even though Johnson has accumulated twice as many top-five finishes as Keselowski, the Sprint Cup 2012 title is clearly Keselowski's to lose.

In fact, if Keselowski can accomplish this feat, he will become only the third driver in modern era racing to have won the championship within the first three years of his Sprint Cup career. Nothing puts the potential of this accomplishment in greater context than recognizing the two drivers who did it before him: Dale Earnhardt Sr. and Gordon.

At Homestead-Miami on Sunday, I expect Johnson and the No. 48 team, led by crew chief Chad Knaus, to race the 1.5-mile track with the wind at their backs. They know their fate and their objective: They must lead the most laps and win the race. Although Keselowski has the advantage of a 20-point lead, he and crew chief Paul Wolfe have to manage their approach, measuring risk while attempting to maintain the rock-solid consistency and performance that have put the No. 2 team in position for this title.

Keselowski simply needs to take care of business. But that's easier said than done. Some of the areas that can get drivers in trouble are places where you can be too careful, like restarts, green-flag pit stops and lap traffic.

The reality is this: As comfortable as the lead appears to be for the No. 2 team, it still has 10 percent of the Chase to complete Sunday. And a lot can happen.