NEW YORK – A Lucian Freud painting sold for $33.64 million at Christie's art auction Tuesday, shattering the record for a piece by a living artist.

The British painter's 1995 portrait of a nude woman sleeping on a sofa, “Benefits Supervisor Sleeping,” sold for just under its high presale estimate of $35 million.

The previous record of $23.6 million was set last November for a Jeff Koons sculpture, “Hanging Heart.”

Contemporary art sold strongly, defying erratic financial markets at a $350 million auction marked by a surprising preponderance of American buying.

Records fell for seven other artists as well.

“It was stupendous,” said Christie's contemporary and postwar art international co-head Amy Cappellazzo, noting it was Christie's second-best contemporary result.

The sale's total was just above the midrange of its presale estimate.

“So much for the weak dollar,” Cappellazzo quipped after the auction. U.S. buyers snapped up 70 percent of the $348,263,600 worth of art sold, while Europeans bought nearly all the rest.

“We didn't expect the dominance of Americans in this sale,” added contemporary art co-head Brett Gorvy. A week ago, U.S. buyers accounted for less than a third of the auction house's Impressionist and modern art total.

The solid results, in which 95 percent of the 57 lots on offer found buyers, brought palpable relief. Some auction officials had privately expressed fears the spring sales could mark the beginnings of a market downturn.

ROTHKO FETCHES $50 MILLION Cappellazzo said the auction house's “sober” approach had paid off. “We read the market carefully. We weren't taking things for granted” after years of exponential increases in contemporary art prices.

Mark Rothko's “No. 15” fetched $50.44 million including commission, far above its $40 million presale estimate.

Warhol's large-scale silkscreen “Double Marlon” of actor Marlon Brando from “The Wild One” went for $32.5 million, while other Warhols also sold well.

“The highest quality is where the greatest number of collectors are competing,” Gorvy said, adding, “We went looking for great material.”

Nine works sold for well above $10 million each, including an unusual offering, Richard Neutra's Kaufmann House, a Palm Springs midcentury modern home that was included in the auction and sold for $16.84 million.

Francis Bacon's “Three Studies for Self-Portrait” was another top lot, fetching just over $28 million, or nearer its low estimate, but Gerhard Richter's “Abstraktes Bild” soared to $14.6 million, far above its $10 million high estimate.

The only significant casualty was Roy Lichtenstein's “Ball of Twine,” which failed to sell when bidding topped out at $12 million.

New records were set for Richard Prince, Tom Wesselmann, Sam Francis, Adolph Gottlieb, Barnett Newman, Robert Indiana and Peter Halley.

The spring sales wrap up Wednesday at Sotheby's,which has assembled an even bigger contemporary and postwar sale than Christie's. The archrivals both scored solid results last week at their auctions of Impressionist and modern art.