The 1954 Mercedes W196 Streamliner driven by Formula One legends Juan Manuel Fangio and Stirling Moss was sold for a record $53 million (51.155mln euros) at auction in Stuttgart.
Five-time world champion Fangio steered it to victory in the 1955 Argentine Grand Prix, with Moss at the wheel in the same season's Italian Grand Prix where he posted the fastest lap time.
The sale makes the W196 the most expensive Formula One car ever sold, doubling the previous record.
The car's predecessor, the Mercedes W196R, held the previous record of 23.35 million euros in 2013.
The auction, carried out at Stuttgart's Mercedes-Benz Museum, had a reserve of 20 million euros and a target price of 50 million euros.
The buyer made the winning bid over the phone, choosing to remain anonymous.
The sale price remains well short of the record for a car, although prices paid for vintage models have skyrocketed in recent years.
In 2022, a rare 1955 Mercedes-Benz SLR coupe from the constructor's collection reached 135 million euros at auction, more than doubling the previous record for a Ferrari 250 GTO set in 2018.
Auctioneers Sotheby's said the W196 Streamliner was one of four known complete examples of the model and the first to be sold to a private buyer.
Mercedes-Benz donated the car to the Indianapolis Motor Speedway (IMS) Museum in 1965. It is one of 11 cars to be sold by the IMS as it narrows its range.
The auction house called the W196 "among the rarest and most beautiful competition cars ever created" and "one of Mercedes-Benz's greatest accomplishments."