Despite a sluggish and, according to some dealers, overstuffed sale of Asian contemporary art, Sotheby’s had a good day yesterday. In the late afternoon, the New York Times reported on its Web site that David Rockefeller has decided to sell a Rothko painting from 1950 at the May 15 sale of contemporary art at Sotheby’s. The estimate has been set at $40 million, almost twice the previous auction record for a Rothko.

That consignment will likely put Sotheby’s on a competitive footing with Christie’s in the upcoming contemporary sale, after several years of trailing behind. (Sotheby’s declined to comment on the consignment in advance of a formal announcement today.)

Yesterday’s Asian sale, however, did little to increase Sotheby’s competitive edge, and, in the eyes of some dealers, exposed some managerial weaknesses. The sale totaled $25.3 million — a number that includes Sotheby’s commission — against a pre-sale, withoutcommission estimate of $17.6 million to $25.3 million. The top two lots were Zhang Xiaogang’s “Bloodline: Three Comrades,” which sold for $2.1 million, and Yue Minjun’s “Goldfish,” which sold for $1.4 million, a record for the artist.

Several dealers criticized Sotheby’s for packing too many works into the sale, including no fewer than 10 paintings by Zhang Xiaogang, the highest-selling Chinese artist. “To put so many Zhang Xiaogangs in makes it very uncomfortable for the sellers,” Michael Goedhuis, of Goedhuis Contemporary, said. The overall quality of the sale’s contents “was pretty lackluster,” he said. “A lot of the works were hovering around the middle of the estimate.”

Others failed to sell because the bidding didn’t rise to the level guaranteed by Sotheby’s. Out of 310 works, 73 went unsold. “They really got kind of greedy in certain areas, and things passed,” a dealer, Martha Sutherland of M. Sutherland Fine Arts, said.

The director of Pékin Fine Arts, Meg Maggio, thought many works passed because the estimates were placed too high. “There were pieces that were bought in” — i.e., passed — “by great artists, and, as far as I’m concerned, the only reason they were bought in was because the estimates were so high,” she said.

Mr. Goedhuis suggested that Sotheby’s was rushing what is still a developing market. “Sotheby’s is manifestly under more pressure than Christie’s is to produce immediate results,” he said. “Christie’s, and Phillips de Pury perhaps even more, have taken a longer view and a more mature view of the market.”

The turnout was small and the atmosphere sedate compared to previous sales. Most of the bidding was by telephone. “There wasn’t much of a buzz in the room,” Mr. Goedhuis said.

Christie’s, meanwhile, held a solid, if unremarkable, sale in another growing field: modern and contemporary Indian art. The sale totaled $8.6 million, in spite of the top lot, Tyeb Mehta’s “Diagonal XV, ” passing.