The successful bidder, a woman from a London art dealership representing an unknown client, won "Le Bassin aux Nympheas" with a bid of 40.1 million pounds, The New York Times reported. In May, "Le Pont du Chemin de Fer a Argenteuil" set an early record when it sold for $41.5 million in New York.
The price was also a record for Christie's in Europe and more than twice the auction house's estimate for the painting.
The painting was one of a series of four. One is in the Metropolitan Museum in New York, one in a private collection that is expected to be left to a museum and one was cut in half in the 1930s.
Most major Monet works are now in museums and unlikely to be up for sale.
"This really is the last chance," Olivier Camu, head of impressionist and modern art at Christie's London, told The Guardian. "It is an extraordinary painting."