Drop-top supercars battle it out in a straight-line dash with a difference.

In a new video clip posted on YouTube, Mat Watson from the UK's carwow pits four of Europe's fastest convertibles against each other in a drag race – the Mercedes-AMG GT C Roadster, Audi R8 Spyder, BMW i8 Roadster, and the McLaren 570S Spider.

Each competitor has a different approach with regards to powertrain: the Mercedes and McLaren both use twin-turbocharged V8s, the Audi a naturally-aspirated V10, while the BMW pairs a three-cylinder turbo petrol engine with an electric motor.

There's a slight twist to this video, too. The first race requires each vehicle to put their roof down before taking off, while the second is a more conventional open-top drag race.

While you might be able to safely guess the result of the standing quarter-mile race, you might be surprised with which vehicle has the quickest roof system, which pretty much decides the first race.

To find out which convertible supercar is the quickest, watch the video below: