Paul Gauguin's "Le vallon" sold for $10,275,503.

LONDON— The summer auction season rocketed off the starting line at Christie'shere, powered by a trio of Pablo Picasso's portraits of his most storied muse/lovers that cumulatively made £42 million, heavily contributing to the £140,019,200 ($227,111,142) tally. Eighty of the 92 lots sold during the two-and-a-half-hour marathon, delivering a stellar 13 percent buy-in rate by lot and 20 percent by value.

It was the slimmest casualty percentage by lot since the top of the market in June of 2007, another strong indicator that the art economy is humming and confidence is in full bloom despite dire international problems in finance and the Euro Zone.

Thirty-one lots sold for over a million pounds, forty over a million dollars, and four world records were set. The result was the third highest for Christie's London in this category, shy of last June's £152.6 million ($226.4 million) total. That sale had a 25 percent buy-in rate by lot.

Tonight it was European buyers who dominated the sale, accounting for 54 percent of the lots sold, while U.S. bidders made up an unusually strong 42 percent, an especially impressive showing considering the weakness of the dollar. Asian buyers made up the other four percent.

Much of the evening's drawn-out success was due to the first 40 lots from the estate of the iconic Swiss dealer Ernst Beyeler, whose museum in a suburb of Basel, the Beyeler Foundation, mounts mostly blockbuster shows and attracts visitors in droves. The work offered from his lionized inventory together realized £44.7 million ($72.5 million) against a pre-sale estimate of £46-67 million and ranged from a group of relatively minor Picasso ceramic to the dealer's own 17th-century Spanish desk, which made an astonishing £289,250 ($469,164) against an £8,000-12,000 estimate.

The section's seemingly low overall tally was due to the pricey buy-in of Claude Monet's late "Nympheas" from circa 1914-17, a much-shopped and widely exhibited painting that remained in the dealer's inventory for good reason and not for a lack of trying. It carried a sky-high £17-24 million pre-sale estimate, too rich for a Monet estate painting that bore the artist's stamped signature, indicating that it was either not fully finished or that Monet was content to keep it cloistered in his studio. The piece bought in at an imaginary £15 million.

That casualty didn't seem to bother Beyeler Foundation director Sam Keller, buttonholed moments after the flop. "I wasn't surprised [it didn't sell], and that's not the picture you give away at a bargain," he noted. "We'd only let it go when it would make a very high price. The museum can show it and it will be very valuable in five to ten years."

But Beyeler's top Picasso, "Buste de Françoise," a color-packed and sensuously curved 1946 portrait of the young artist and Picasso mistress Françoise Gilot, met expectations and bounded past its £7-9 million estimate, selling to New York dealer William Acquavella for £10,681,250 ($17,324,988). Another Beyeler highlight was Paul Gauguin's "Las Vallon," a tropical Tahitian landscape from 1892 (est. 5.5-8.5 million), sold to Paris dealer Lionel Pissarro of the Giraud Pissarro Segalot combine for £6,425,250 ($10,421,756).

Between major paintings, such as Pierre-Auguste Renoir's large-scaled and widely exhibited "La Source (Nu Allonge)" from circa 1902 (est. £4-6 million) that sold to a telephone bidder for £5,081,250 ($8,241,788), lesser objets, like the small Diego Giacometti side table "Gueridon aux Bourgeons"(est. £50-70,000), which supported the Beyeler gallery's fax machine, sold for a wildly inflated £646,050 ($1,047,893).

When the Renoir was being auctioned, two overexcited Japanese gentlemen seated in the front row leapt from their seats to take a closer look at the painting, startling auctioneer Jussi Plykkanen, who navigated the sale with great elan.

Call it the Beyeler factor — the late dealer, who died in February 2010 at the age of 88, can still make art move. A fantastic yet editioned Henri Matisse, "Oceanie, la Mer" from 1946-57, one of 30 screen prints on linen produced, sold to a telephone bidder for £2,953,250 ($4,790,172) against an estimate of £500-700,000. One of the underbidders left far behind was Paris dealer Daniel Malingue, who dropped out at around £1.2 million, at that point already a retail plus price.

It was instantly clear that the salesroom had a big appetite, as evidenced early on in the 52-lot-strong various-owners' portion of the sale. In that round a rare-to-market, vividly executed August Macke, "Im Bazaar," a page-sized 1914 work of watercolor and pencil on paper (est. £600-800,000) sold to telephone bidder for a record £3,961,250 ($6,425,148).

New York and London dealer Daniella Luxembourg was the underbidder. "It's really a strong market," said Luxembourg, who snagged Paul Klee's "Gelande des Ubermutes" (est. £200-300,000) earlier for £421,250 ($683,268). "Whenever there was something of good quality, it brought a great price."

Other artist records at the sale included Klee's ebullient dancer "Tanzerin" from 1926 (est. £2-3 million) that sold to an unidentified woman bidding in the salesroom for £4,185,250 ($6,788,476). Though not part of the Beyeler estate, the work's provenance was from the dealer's collection, another indicator of his wide-ranging mark on the international art market.

Beyeler's touch, however, could not be credited with the stellar performance of the evening's cover lot, Picasso's "Jeune Fille Endormie" from 1935. The portrait of the artist's young mistressMarie-Thérèse Walter snoozing in an ornately decorated room sold to London dealer Alan Hobart for £13,481,250 ($21,866,588), overshooting its £9-12 million estimate.

Towards the end of the bidding war, Hobart impatiently held up his paddle — number 122 — waving it at the auctioneer. "He drags the sale out," said Hobart, explaining his action. But that temporary upset did not impact his mood. "We're delighted with the price and the condition of the picture is pristine, as good as when Walter Chrysler bought it," he said.

Hobart was referring to the much earlier purchase by that late automotive magnate, who acquired the painting at Sotheby's Parke Bernet in New York in February 1950 for $4,000. Remarkably, an anonymous patron bequeathed the painting to the University of Sydney in Australia to fund "transformative health research" in diabetes.

But the youthful Marie-Thérèse was outgunned by another Picasso mistress, the meanly depicted and brazenly unattractive Dora Maar portrait "Femme Assise, Robe Bleue" from 1939 (est. £4-8 million), that sold to Paris and Geneva based collector Dimitri Mavrommatis for the top-lot price of £17,961,250 ($29,133,148).

"Tonight, art history won in a way," said Christie's international Impressionist and Modern art headThomas Seydoux, referring to the more important composition of Maar triumphing over the electric beauty of Marie-Thérèse.

The Impressionist-Modern evening action resumes on Wednesday at Sotheby's.

Picasso's "Jeune fille endormie" sold for $21,731,775 at auction.

Picasso's "Buste de Françoise" sold for $17,218,175.

Ernest Beyeler's desk sold for $466,271.

Claude Monet's "Nymphéas" was bought in.