Picasso's mistress tempts art lovers with an auction estimate of $50m

The world's most acquisitive art collectors have eyes only for New York this week as the rival auction houses Christie's and Sotheby's unleash spring Impressionist and modern art sales with exceptional offerings from masters including Van Gogh and Picasso.

Anticipation was keenest ahead of the opening session at Sotheby's last night, where the undoubted star of a dazzling range of lots was Dora Maar with Cat, painted by Picasso in Paris in 1941. The portrait of his mistress was expected to sell for $50m (£27m), propelling it into the top 10 of the world's most expensive pictures.

A high standard had already been set across town at Christie's, however, which was basking yesterday in the success of its sale on Tuesday night. Two other paintings by Picasso, Le Repos (1932) and Portrait of Germaine - tantalised buyers, some bidding through representatives or over the telephone.

The greatest buzz in the Christie's sale room, however, surrounded a single painting by Van Gogh, L'Arlésienne, Madame Ginoux (1890), a portrait of a café owner in Arles who was also the subject of works by his peer and friend in that period Paul Gauguin.

If there was any sense of disappointment at Christie's, it may have been because the Van Gogh fetched $40.3m, including commissions. This appeared rather a bargain - the estimate had been between $40m and $50m. There was speculation that the telephone bidder was Sammy Ofer, an Israeli collector.

By the end of the sale Christie's had drawn bids totalling $180.2m, the second highest it has achieved for an Impressionist and modern art sale and the best for the auction house since 1990, when Van Gogh's Dr Gachet sold for $82.5m.

"It is a strong market without being a crazy market," Christopher Burge, honorary chairman of Christie's America and the auctioneer for the evening, said afterwards. "This is not a market in any way out of control."

The best drama was generated by Picasso's Le Repos. At the end, two bidders were vying for the work, one on the telephone competing against Larry Gagosian, the Manhattan gallery owner, who finally placed the highest bid - $34.7m, way above the $20m estimate - acting for a client.