A portrait of Jeanne Hebuterne painted by Italian artist Amedeo Modigliani a year before his death in 1920 sold on Wednesday for 26.9 million pounds ($42.3 million), above the high estimate set by Christie's auctioneers.
"Jeanne Hebuterne (au chapeau)" was the leading lot at the impressionist, modern and surrealist sale in London which brought in a total of 136.5 million pounds, a record at Christie's for the equivalent auction in London in February.
The total underlines the strength of the high-end art market, with ultra-wealthy buyers and institutions from markets like Russia, China and the Middle East bidding against more established collectors in Europe and the United States.
Modigliani met Hebuterne towards the end of his life and they had a child together. The day after the artist died aged 35, his inconsolable partner jumped out of a window killing herself and their unborn second child.
Another notable success on the night was 19th Century French painter Berthe Morisot's "Apres le dejeuner" which fetched seven million pounds, well in excess of expectations of between 1.5 million-2.5 million pounds.
The total was a record price for a female artist at auction.
Morisot was famously captured by Edouard Manet wearing a black hat, a work which is currently hanging at a Manet exhibition at the Royal Academy near Christie's headquarters.
Rival Sotheby's had the top lot of two days of major sales in London, with Picasso's portrait of his mistress Marie-Therese Walter selling for 28.6 million pounds on Tuesday.
Overall Sotheby's sold art worth 121.1 million on the night.