A Warhol self-portrait went for a record £2m
More than 60 pieces of art went under the hammer, with 15 of the 45 artists involved setting new records.
Five Warhols and two Richters were among the top 10 lots, with the top two spots going to Richter's 180 Farben and Kerze, which each sold for just under $4m (£2.7m) including commission.
Sotheby's contemporary art specialist Laura Paulson called the results "fantastic".
"It was a very solid evening with a lot of bidding in the room as well as on the telephone," Paulson said.
A self-portrait of Warhol, rendered in yellow in 1986 a year before the artist's death, went for more than $3m (£2m), well above the high estimate of $2m (£1.3m).
It also sets a record for a Warhol self-portrait.
Warhol's Five Deaths, an orange silk-screen of a car wreck from the early 1960s, fetched $3m.
Three other Warhols - Four Jackies, Superman and an earlier self-portrait - all sold for around $1.8m (£1.2m) each.
Sotheby's said the steadily rising prices for his work may be due to collectors thinking there were fewer Warhols available than previously thought.
Disappointment
Other highlights included Alexander Calder's Dos discos blancos, which fetched just under $2m, well above its high estimate of $1.2m (£820,000).
Willem de Kooning's Untitled XI went for nearly double its estimate at $1.6m (£1m).
However, it was not all good news as some artists including Cy Twombly, Francis Bacon and Mark Rothko.
Their works, which had estimates of up to $3.5m (£2.4m), failed to sell.