Jimmie Johnson won an unprecedented fourth straight NASCAR championship in style at the Homestead-Miami Speedway on Sunday. Johnson qualified on pole, ran at the front, and finished a strong fifth as he led Hendrick Motorsports team-mates Mark Martin and Jeff Gordon to a 1-2-3 championship sweep.

So Johnson has equalled his mentor Gordon’s tally of four championship wins. The only drivers to claim more titles are NASCAR legends Richard Petty and Dale Earnhardt, who both won the top prize seven times.

Johnson, 34, has achieved his success in only eight years of Sprint Cup racing. He made his debut with Hendrick’s team near the end of 2001 and started his Cup career in earnest the following year. Jimmie won three races and finished fifth in the championship that year, then won three more races in 2003 and finished second in the points to Matt Kenseth. In ’04, Johnson won eight races – more than anyone else – and again finished as runner-up, only eight points behind Kurt Busch.

He had a comparatively poor season in 2005, but since then it’s been Johnson all the way. He won five races and the title in ’06, scored 10 wins on the way to his second title in ’07, added seven more last year as he equalled Cale Yarborough’s record of three consecutive championships, and established a new standard this year with seven more wins and that historic fourth title.

Johnson is with the best team in the business and is in the prime of his career; before qualifying at Homestead he and team owner Rick Hendrick announced a contract extension until 2015. That means Johnson could catch and even surpass Petty and Earnhardt’s mark. Mind you, it will be difficult to match Petty’s tally of 200 wins accumulated over a 35-year career, while Earnhardt won 76 races over 25 years. Johnson’s 47 victories thus far rank him 13th on NASCAR’s all-time race winners’ list.

But for most NASCAR fans, Johnson is a Milquetoast Californian. In popularity polls he ranks outside the top 10 and way behind team-mate Dale Earnhardt Jr, who is by far NASCAR’s most popular driver and easily the most successful in terms of income from merchandise sales and advertising endorsements. Yet Earnhardt, 35, has just endured the least successful season of his career, failing to come close to winning a race and finishing a desultory 25th in the points.

After peaking three years ago NASCAR’s crowds and TV ratings have been in steady decline over the past two years. Figures for both were down between 10-20 per cent this year, leaving the sport’s rulers hoping that Earnhardt will somehow rebound in 2010.

But in the real world, that’s unlikely. Johnson’s continued dominance is much more probable.