Defending NASCAR Sprint Cup champion Jimmie Johnson scored his sixth win of the year on Saturday night at the Charlotte Motor Speedway, pulling 90 points clear of closest challenger Mark Martin in the title race. It was Johnson’s 46th Cup win and his first in four years at Charlotte as he closes on an unprecedented fourth straight championship. None of his title rivals had good races, leaving the 34-year-old looking likely to clinch the crown before the season finale at Homestead-Miami Speedway.

“If we don’t have any problems, I feel we’ve got a good chance to win the championship,” said Johnson. “But the unknowns are what we can’t control. That’s why we don’t want to get too emotionally wrapped up in this thing, and have somebody come by and slap us in the face and take us out. We’re just trying to keep our guard up.”

NASCAR races next weekend at the tiny, half-mile Martinsville oval in Virginia, where Johnson is considered the man to beat. He’s won four of the last five races run there so is confident of doing well. But Jimmie worries about the following race on November 1 at the high-banked Talladega Superspeedway in Alabama, where multi-car accidents are a fact of life.

“That’s the track where you don’t have any control,” he said. “But at the same time, we’re only halfway through [the Chase for the Cup]. So much can happen. Somebody at Martinsville can lose their brakes and clean you out. With the double-file restarts, there’s going to be a lot of bumping and banging. It’s a nice points lead, but there’s no need for anybody to get excited yet. We’ve got good tracks ahead for us, so from a team standpoint we’re excited and optimistic. But there’s a lot of danger out there and we’ve got to be smart.”

Of the other contenders for this year’s championship, Martin and Juan Pablo Montoya collided at Charlotte on a restart and wound up finishing 17th and 35th. Montoya had qualified 18th but moved rapidly through the field to fourth before damaging his car in the collision with Martin and Clint Bowyer. Montoya had to pit for repairs and eventually finished four laps down, falling to sixth in the points, 195 behind Johnson. Martin was able to hang on to the lead lap but he’s now 90 points behind his Hendrick team-mate.

Jeff Gordon, who was fourth at Charlotte, is third in the points, 135 behind Johnson. Tony Stewart was another to have a poor race, finishing 13th. He hangs onto fourth in the championship, 155 points off the lead.

Last year Johnson equalled NASCAR legend Cale Yarborough’s feat of winning three titles in a row with Junior Johnson’s team back in 1976-78. But nobody, including seven-time NASCAR champions Richard Petty and Dale Earnhardt, has ever won four consecutive titles. If Johnson pulls it off not only will he be the first to do so, but he’ll also equal Gordon’s tally of four championship wins. Gordon is NASCAR’s most successful active driver and a part-owner of Johnson’s car.

In the prime of his career, Johnson could easily race for another 10 years. He’s likely to become not only one of NASCAR’s most successful drivers of all time, but could surpass Petty and Earnhardt’s tally of seven title wins. First, he has to write some NASCAR history by wrapping up this year’s Sprint Cup, and based on what we saw at Charlotte that day isn’t far off.