The Gatorade Duel, formerly known as the Daytona Twin Qualifiers, and later Twin 125's, is a preliminary event to the Daytona 500 held each February at Daytona International Speedway. It consists of two races of 150 miles each. They are usually held, weather permitting, on the Thursday prior to the actual Nextel Cup race on Sunday. Qualifying for the Daytona 500 is unique in NASCAR. Only the pole-sitter and the driver to the outside of him (the "outside pole") are determined by the ordinary qualifying process of timed laps. The rest of the qualifying field, and their order of start, are determined by the drivers' placement in these two races, each of which consists of half of the rest of the drivers attempting to qualify, with the better placements obviously going to the most successful drivers.

The races were originally 100 miles in length when established in the 1959 Daytona 500, and has undergone three format changes. In 1968, the races were stretched from 100 to 125 miles to change pit strategy, but the races were cancelled because of inclement weather, the only time it has happened. In 1971, the races were dropped from the NASCAR Grand National schedule as championship NASCAR races which paid points towards the championship as part of Winston's change to requiring races to be at least 250 miles. The races were lengthened in 2005 to 150 miles, and in deference to NASCAR's new Top 35 exemption, the grids changed from even-odd qualifiers to a combination of top 35 even-odd from the previous year's owner points and then the rest of the drivers' speed. [1]

See also: List of current NASCAR races