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

Danica Patrick to make NASCAR Sprint Cup debut at Daytona 500

Danica Patrick plans to make her debut in NASCAR's premier Sprint Cup Series at the sport's crown-jewel race, the Daytona 500, next Feb. 26 and is eyeing a possible full-time Cup ride in 2013.

Patrick, 29,will drive the No. 10 Chevrolet for Stewart-Haas Racing, the team co-owned by two-time Cup champion Tony Stewart.

Patrick just finished her full-time career in the Izod IndyCar Series, in which she won one race in seven years, to drive full-time in NASCAR stock-car racing.

In an announcement at Texas Motor Speedway, site of the next Cup race Sunday, Stewart-Haas and Patrick said she would drive a total of 10 Cup races next year while also competing all season in NASCAR's second-tier Nationwide Series.

Besides Daytona, Patrick's Cup schedule includes Darlington (S.C.) Raceway, Bristol (Tenn.) Motor Speedway, Atlanta Motor Speedway, Chicagoland Speedway, Dover (Del.) International Speedway, Texas Motor Speedway and Phoenix International Raceway.

Her two other Cup appearances will be determined later.

"Our goal with Danica's schedule is to try and maximize her 10 races with us so that she's as prepared as she can possibly be for a full-time Sprint Cup schedule in 2013," Stewart said in a statement.

Patrick, who is driving in this Saturday's Nationwide race at Texas, also said her helmet and race car would carry paint schemes honoring two-time Indianapolis 500 winner Dan Wheldon, who was killed last month in an IndyCar race in Las Vegas.

-- Jim Peltz

Photo: Danica Patrick and team co-owner Tony Stewart unveil Patrick's No. 10 Chevrolet for the 2012 NASCAR Sprint Cup Series during an event at Texas Motor Speedway on Friday. Credit: John Harrelson/Getty Images