The reigning champion continued rewriting his Chase statistics this year, following his third win in the first five races of the series' play-off on Saturday at Lowe's Motor Speedway. Johnson now averages at 3.2 finish over the first half of the Chase - his best ever - and his closest rival, team-mate Mark Martin, already trails him by 90 points.
Next up in the calendar is Martinsville, where Johnson has won four out of the last five races. Despite all that, Johnson prefers to keep his emotions in check as he reckons it may take only one bad race for him to lose the championship lead.
"If somebody spins out, you get caught up in it, contact with another car and there's a tyre rub, fender is on the tyre, you come down pit road, puncture a tyre, whatever it is, those elements are still out there," said Johnson.
"I feel very good about racing for the championship. If we don't have any problems, I feel that we've got a very good chance to win the championship, racing for it.
"But the unknown is what we can't control. We don't want to get ourselves too emotionally wrapped up in this thing and have something come by and slap us in the face and take us out, so we're just trying to keep our guard up."
Johnson's crew chief Chad Knaus echoed his driver's approach, saying that besides the inherent risks of close racing at upcoming tracks like Martinsville and Talladega, there are other elements that may hit their chances when they least expect.
"It happens to everybody," said Knaus. "It's all about circumstances and timing. We're fortunate over the course of the last couple years we haven't had a significant failure in the Chase, but it is very, very possible, and the potential is there every time you go on the race track."
Johnson's boss Rick Hendrick believes it is still too early to draw any conclusions about the championship and reminded that the problems that other Chase drivers have faced already, could eventually affect Johnson in coming races as well.
"You know, we've got five more (races) to go," said Hendrick. "I think what I try to keep in mind is the same thing that's happened to the guys that got them behind could happen to us.
"I'd rather be this far ahead than be behind, but you look at Denny Hamlin - he has been running great and he had two problems here that put him in the shape he's in.
"We've got Talladega coming up. You could have a problem at Martinsville. This double file restart, I don't think you can have enough points. It's just too early into the Chase."
Johnson last failed to finish a race during the Chase in 2006, when he crashed out at Talladega while fighting for victory with Brian Vickers and Dale Earnhardt Jr. Since then, his worst finish during the play-off has been 15th at Texas and at Homestead last year.
La Liga round-UpRivals say Johnson now hard to catch
