Sotheby’s auctioned off $114.5 million worth of postwar and contemporary art last night, the highest ever total in the category for the house. The sale was led by David Smith’s massive stainless-steel sculpture “Cubi XXVIII” (1965), which sold for an equally massive price: $23.8 million, the highest ever for a postwar work. It broke the auction record of $22.4 million set the previous night at Christie’s by Mark Rothko’s “Homage to Matisse,” which had contributed to a $157.4 million sale for that house.

Two formidable dealers, Dominique Levy of L &M Arts and Larry Gagosian, began bidding head to head when the Smith reached $17 million, besting each other in quarter-million and half-million dollar increments. Mr. Gagosian eventually won the sculpture, the 28th of a group of 28 large-scale works made by Smith, and one of only seven not in museums.

“I was very sorry not to get it,” Ms. Levy said. “This sculpture very much deserves the record.”

Classic postwar works rallied buyers throughout the evening, while a few high-priced pieces of the most recent vintage, most notably two works by Richard Prince, failed to sell. Six of 54 lots did not find buyers.

“It was an incredible result on the Smith,” dealer Harry Blain, of Haunch of Venison Gallery in London, said. Overall, he said, “It was a very strong performance. If you look at people who were buying, they weren’t throwing money at things but were determined and were testing things.”

Two Cy Twombly paintings broke the artist’s previous record at auction of $5.6 million. Mr. Twombly’s blowsy, pink rococo painting “Untitled (Rome)” (1961) sold for $8 million to Mr. Gagosian, who is the artist’s gallerist and is currently hosting a show of new Twombly paintings. A few minutes later, Mr. Twombly’s scribble-on-blackboard painting “Untitled (New York City)” sold for $8.7 million. Mr. Gagosian took a keen interest in this work as well. As Sotheby’s auctioneer and head of contemporary art, Tobias Meyer, prodded the room for takers above what turned out to be the final price, Mr. Gagosian asked, “Are you selling it?”

“You don’t see two Twomblys like that come on the market very often,” Rachel Mauro, president of Dickinson Roundell Gallery, said. “The sale wasn’t as strong as Christie’s. But obviously the market is very strong.”

Records were also set for works at auction by four other artists: Louise Bourgeois, whose giant “Spider” (1997-8) sold for $3 million; Hiroshito Sugimoto, whose suite of seven wax portrait photos of Henry VIII and his wives sold for $744,000; Francis Alys, and Vija Celmins.

“It was super quality,” collector Aby Rosen said of the sale. “The bad stuff was passed on. People know what they’re buying.”

The consecutive record-setting nights at Christie’s and Sotheby’s provided yet more evidence that the contemporary art market is billowing with money and energy. Other top lots last night included Andy Warhol’s “Jackie Frieze” (1964), which went for $9.2 million, and his “Flowers” (1964), which went for $6.7 million, both to buyers on the phone. Francis Bacon’s “Three Studies for Self-Portrait” (1976) sold for $5.2 million to Andrew Fabricant of Richard Gray Gallery.

When so many buyers in the salesroom are dealers, it is striking to see a private collector show up and buy with open enthusiasm. But Miami collector Marty Margulies hugged his female companion as if he’d just won at the races when he realized he’d won Warhol’s “Set of Five Boxes” (1964) for $1.2 million. The house had assembled for this sale five of Warhol’s wood boxes painted to look like packaging from Brillo, Campbell’s, Del Monte, Heinz, and Kellogg’s.

“It’s high-end entertainment, with no admission fee,” said collector and former Disney president Michael Ovitz, who sat in the front row but did not bid. He should know.

Tonight, Phillips de Pury and Company will test the depth of buyers’ passion for the newest of the new. Its sale focuses on work made after 1980 and is estimated to make between $18.8 million and $26.8 million.

Star Lots of Sotheby’s Postwar and Contemporary Sale

David Smith, “Cubi XXVIII” (1965) Sold for: $23.8 million Presale estimate: $8 million to $12 million Smith made 28 “Cubi,” and 21 of these large stainless steel constructions are owned by museums. This gate-like “Cubi” is 9 feet tall and is set off by two tilted squares. Smith’s previous auction record of $4.9 million was set Tuesday night at Christie’s; the previous record for any postwar work was the $22.4 million paid for Mark Rothko’s ‘Homage to Matisse,’ also at Christie’s on Tuesday.

Andy Warhol, “Jackie Frieze” (1964) Sold for: $9.2 million Presale estimate: $8 million to $10 million Thirteen Jackies, all based on a photo of the former first lady at the president’s funeral, compose an unusual “disaster” painting. Warhol’s “Death and Disaster” series deployed images of car crashes, electric chairs, and race riots. Add to that a beautiful woman, her face marred by a mourning veil.

Cy Twombly, “Untitled (New York City)” (1968) Sold for: $8.7 million Presale estimate: $8 million to $10 million This Twombly, from his coveted blackboard series, features looping scribbles, which descend like clef notes. The artist’s previous record at auction was $5.6 million.

Cy Twombly, “Untitled (Rome)” (1961) Sold for: $8.0 million Presale estimate: $6 million to $8 million. Mr. Twombly, who has lived in Rome since 1957, has worked up the surface of this painting into a pink froth. It had been in a private collection since the year after it was painted.

Andy Warhol, “Flowers” (1964) Sold for: $6.7 million Presale estimate: $4 million to $6 million A bigger flower painting of two blooms sold at Christie’s last spring for $7.9 million. This giant still life features four light-blue hibiscus flowers against green-and-black grass. Warhol made just three flower canvases of this size.

Jean-Michel Basquiat, “El Gran Espectaculo (The History of the Black People” (1983) Sold for: $5.2 million Presale estimate: $4.5 million to $6.5 million One of the centerpieces of the current traveling Basquiat retrospective, this three-part stretcher painting races through a few thousand years of history in Basquiat’s highly personal, highly political system of hieroglyphics.

Francis Bacon, “Three Studies for a Self-Portrait” (1976) Sold for: $5.2 million Presale estimate: $4 million to $6 million A new Bacon record of $10.1 million was set Tuesday night at Christie’s for ‘Study for a Pope I’ (1961). While not as iconic, this triptych is a formally assured portrait of modern man in disarray.

Jeff Koons, “Lifeboat” (1985) Sold for: $3.4 million Presale estimate: $3 million to $4 million An entirely too heavy bronze lifeboat stands with Mr. Koons’s vacuum cleaners as one of his most overt tributes to Duchamp.

Damien Hirst, “The Most Beautiful Thing in the World” (2003) Sold for: $1.3 million Presale estimate: $950,000 to $1.2 million This elaborate mosaic of butterfly wings encased in a round frame set a record for any Hirst painting at auction.