A 1959 Ferrari 250 GT LWB California Spider led Gooding & Company's August 21 sale at Pebble Beach, realising $18.1m.
It's one of only nine such Spiders built with alloy coachwork, which dramatically reduces the weight. They were designed exclusively for competition.
This example was raced extensively between 1959 and 1964 and has since won numerous concours and other accolades.
The auction house explained in the run up to the sale: "Considering its incredible rarity, superb racing record, and faultless presentation, this alloy-bodied California Spider is surely among the greatest Ferrari competition cars and, quite possibly, the ultimate open 250 GT."
A 1960 Ferrari 250 GT SWB Berlinetta Competizione made $13.5m.
The car is one of the earliest short wheelbase (SWB) versions to roll off the production line.
It's also an iconic piece of racing history, having achieved a seventh place ranking at the 1960 24 Hours of Le Mans.
After the race it was shipped to the US, where it passed through the hands of several collectors.
It has since been repainted in the livery it wore at Le Mans.
This weekend's sales in California have yielded some impressive results, most notably the two records set at RM Sotheby's for the most valuable British and American cars to sell at auction.
Meanwhile, a Bugatti Type 51 set a record for its type at Bonhams.
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