The 25-year-old learned she had won the title after finishing second with Alain Gautier in the double-handed Transat Jacques Vabre race.

Gautier and MacArthur spent more than 14 days at sea, travelling nearly 5,200 miles from France to Brazil.

MacArthur has won the Fico-Lacoste World Championship, which is based on points scored in ocean races.

She said: "It really is fantastic.

"I remember years ago looking at my name appearing at the very bottom of the list when I did my first race, and to see it move up to the top of the list is incredible.

"I still feel like 'how on earth can it be me'."

The world title completes a remarkable year for MacArthur, who last week was named female world sailor of the year by the International Sailing Federation.

Record breaker

She became a household name in February when completing the Vendee Globe solo round-the-world race.

MacArthur was the youngest competitor to ever finish that race, the fastest woman around the globe and only the second person to go round-the-world solo in under 100 days.

In the Transat Jacques Vabre, Gautier and MacArthur, on board Kingfisher-Foncia, had been in the lead for most of the race.

But they were overtaken during the last night after their boat was damaged.

The pair had to settle for second place, crossing the finish line in Bahia some three-and-a-half hours after Frenchman Franck Cammas and Swiss co-skipper St�ve Ravussin.