Sotheby's kicked off a two-week series of major art auctions in New York on Tuesday by selling Pablo Picasso's rainbow-hued double portrait, "Women Reading," for $21.3 million.

In this 1934 painting, Picasso's mistress, Marie-Thérèse Walter, and her sister, Genevieve, hover over an open book, their faces painted in cheery shades of sky blue and mint green. Sotheby's expected the painting to sell for between $25 million and $35 million, but only two bidders joined in the competition and the dogfight was short.

The winner was a Chinese man who wore blue jeans and cradled a cell phone to his ear as he bid from his seat in the house's Manhattan salesroom. Afterward, he declined to give his name.

Sotheby's tried to leverage Picasso's global appeal by packing its $170.4 million sale with pieces spanning the artist's seven-decade career, from early Picasso portraits of rosy-cheeked children to late-era nudes. The strategy largely worked: Eight of the sale's 10 Picassos found buyers, including a 1970 portrait, "Couple with a Guitar," that came from the estate of San Francisco collector Dodie Rosekrans and sold to a Russian telephone bidder for $9.6 million, just below its $10 million low estimate. Picasso's 1930 view of his first wife, Olga, "Woman," also sold to a telephone bidder for $7.9 million, over its $5 million high estimate.

But the mood in the packed salesroom felt fickle off and on, with 15 of the sale's 59 works going unsold—a sign that seasoned buyers crave masterpieces and are willing to bypass anything deemed ho-hum.

Paul Gauguin's "Young Tahitian," a nine-inch-tall wooden bust sculpted during the artist's first trip to Tahiti around 1893, sold following a single bid for $11.2 million, over its $10 million low estimate. Gauguin, who rarely made sculptures, adorned this tamanu-wood carving of a child with several red-coral and shell necklaces. In an endearing twist, he also gave the work to the daughter of his friend and art critic Jean Dolent.

Expressionist Alexej von Jawlensky's vivid portrait his wife from 1912, "Woman with a Green Fan," sold for $11.2 million, within its $8 million to $12 million estimate. Paul Delvaux's surrealist view of two lounging women from 1946, "Caryatids," sold for $9 million, well over its $5 million high estimate.