Updated

The Budweiser Duel at Daytona International Speedway -- the twin 150-mile qualifying races -- will determine the starting lineup beyond the front row for the Feb. 24 Daytona 500.

In last Sunday's time trials for the Daytona 500, Danica Patrick won the pole position, becoming the first female to win a pole for a race in NASCAR's premier series (Sprint Cup). Jeff Gordon will share the front row with Patrick after finishing second in time trials. They are the only drivers who secured their starting positions for the 500-mile race.

The starting spots for each of the two qualifying races was determined in time trials. Drivers who finished in the odd-numbered positions were assigned to the first race, while drivers who finished in the even-numbered positions were placed in the final event. Patrick will start first in the 23-car field for the first Duel, while Gordon will lead a field of 22 cars in the second Duel.

Dale Earnhardt Jr. blew an engine during Wednesday's practice and will have to start from the rear of the field in race one. Earnhardt Jr. had earned the sixth starting position for that qualifier following his 11th-place finish in time trials.

The top-15 finishers in each Duel race -- not including Patrick or Gordon -- will fill positions 3-32 in the starting lineup for the Daytona 500. The top-15 finishers in the first race will make up the inside row (odd-number starting positions), while those who finish 1-15 in the second event will line up on the second row (even-number starting spots).

Starting positions 33-36 will go to those drivers who did not finish in the top-15 in their respective qualifying races but were among the top speeds during time trials. Spots 37-42 will go to the top-six cars in the 2012 Sprint Cup owner point standings that are not already locked in. The 43rd and final position is reserved for the most recent past series champion. If there is no eligible past champion, that spot will revert back to last year's owner points.

In addition to Patrick and Gordon, 11 other drivers are guaranteed a starting spot in the Daytona 500, no matter where they finish in the Budweiser Duel.

Trevor Bayne, Ryan Newman, Tony Stewart and Kasey Kahne are locked in based on their speed/time in time trials. Bayne posted the third fastest qualifying lap, followed by Newman, Stewart and Kahne.

Brad Keselowski, the reigning series champion, Clint Bowyer, Jimmie Johnson, Greg Biffle, Denny Hamlin and Ricky Stenhouse Jr. have a spot reserved in the 500 by virtue of last year's owner points. Stenhouse, a rookie in Cup this season, is in the seat of the No. 17 Roush Fenway Racing Ford, previously held by Matt Kenseth.

Kurt Busch, driving the No. 78 Furniture Row Racing Chevrolet this year, is locked in since he is the most recent past champion (2004).

Mike Bliss and Brian Keselowski, who is Brad Keselowski's elder brother, finished 44th and 45th, respectively, in time trials. The only way these two drivers can make the Daytona 500 is to race their way in during the Duel. Keselowski is competing in the first race, and Bliss is in the second event.

Last year, Stewart won the first qualifying race -- known then as the Gatorade Duel -- while Kenseth took the checkered flag in the second event. Kenseth also won the Daytona 500, which was delayed one day for the first time in its history due to rain.

Series: NASCAR Sprint Cup. Date: Thursday, Feb. 21. Race: Budweiser Duel (Daytona 500 twin qualifiers). Site: Daytona International Speedway. Track: 2.5-mile tri-oval. Start time: 2 p.m. ET. Laps: 60 (each qualifier). Miles: 150. 2012 Winners: Tony Stewart (race 1), Matt Kenseth (race 2). Television: Speed. Radio: Motor Racing Network (MRN)/SIRIUS NASCAR Radio.