A recently rediscovered 6-by-6 foot Andy Warhol self-portrait doubled its pre-sale estimate to fetch £10.8 million pounds ($17.4 million) at a London auction on Wednesday.

Christie's evening sale of Post-War and Contemporary art brought in a total £61.4 million ($99 million), well above the presale estimate and the highest amount for the series since 2008.

Earlier in the week Warhol also performed well with his Nine Multicoloured Marilyns selling for £3.17 million ($5.1 million) against an estimate of £2-3 million at Sotheby's where four other Warhols fetched on the high end of estimates to bring a total £5.3 million ($8.5 million).

Gerhard Richter’s work also went for strong prices during the week of sales. His monumental Abstraktes Bild of 1990 edged above estimate to bring £7.2 million ($11.5 million) at Sotheby's while another one of his abstract works doubled the estimate to fetch £3.2 million ($5 million) at Christie's.