Tony Stewart leads halfway through NASCAR race in Phoenix

The battle for NASCAR's Sprint Cup title went off as advertised Sunday.

Tony Stewart, who started the day trailing Carl Edwards by only three points in the championship standings, was leading at the halfway point of the Kobalt Tools 500 at Phoenix International Raceway.

But Edwards kept up the pressure, running a close third behind Stewart and second-place Matt Kenseth, who was the race pole-sitter.

Stewart was aggressive from the moment the green flag waved, charging from his eighth-place starting spot to the lead in less than 40 laps of the 312-lap race on the one-mile Phoenix oval.

Brad Keselowski was fourth and A.J. Allmendinger fifth. Kyle Busch, who started near the back of the 43-car field, had climbed to 13th. Dale Earnhardt Jr. was 23rd.

Overall, though, passing proved difficult for the drivers and much of the racing was single file on the newly repaved Phoenix International layout.

This is the next-to-last race in the 10-race Chase for the Sprint Cup title playoff; the finale is next Sunday at Homestead-Miami Speedway.

--Jim Peltz in Avondale, Ariz.

Photo: The field takes the green flag Sunday at the NASCAR Sprint Cup Series race at Phoenix International Raceway. Credit: Christian Petersen / Getty Images