A Modigliani nude painting was sold to an unnamed Chinese buyer at Christie's on Monday for $170.4 million, the second-highest price ever for a work of art at auction, as deep-pocketed collectors continue to pay, and pay big, for some rare masterpieces up for sale in this year's autumn auctions season.

The final price for the 1917-18 portrait "Nu couche" (Reclining Nude) — under the hammer for the first time ever — was second only to Picasso's "Les femmes d'Alger" (Women of Algiers) which sold for $179 million at Christie's in May.

While the buyer was not identified, Christie's said the painting was bought by a private Chinese collector. Asian collectors have been especially active in the art market for the past several seasons.