A Picasso sculpture has sold for a record price $6.7m (�4.2m) at Christie's in New York, while two paintings, Monet's waterlilies and a Modigliani portrait, both remained unsold.

The sale of La guenon et son petit, a 1951 bronze of a baboon cradling her young, drew enthusiastic bidding and a final price just under its estimate of $7m (�4.47m), making it the sale's top lot.

The previous record for a Pablo Picasso sculpture is $4.9m (�3.1m).

Christie's number-two estimated lot, Modigliani's La robe noire, which had an estimated selling price of between $9m (�5.7m) and $12m (�7.6m), failed to sell when bidding peaked at $7.5m (�4.7m).

Casualty

Similarly, Monet's Le bassin aux nympheas, estimated at $10m (�6.39m) to $15m (�9.59m), was another casualty.

The circa 1917 to 1919 work from the artist's waterlilies series - which was painted at Monet's house at Giverny - failed to sell when bidding topped at $8.5m (�5.4m).

The failure of the Monet and the Modigliani to find buyers was a case of the works having carried "slightly too strong an estimate", according to Christie's auctioneer Christopher Bulge.

A previous Picasso sculpture sold for $4.9m (�3.1m)

"They were just too expensive for right now," he said.

The Modigliani portrait, he added was "frankly overpriced".

Christie's international managing director Marc Porter said the sluggish state of the economy was not to blame for the two lots going unsold.

"It had much more to do with estimating strategy," he said.

"If the economy were a factor, the paintings in the $5m (�3.2m) range wouldn't have been any different," Porter said, referring to a host of works by Leger, Gauguin, Cezanne and Caillebotte which sold for more than $4m (�3.2m) apiece.

"Prices like that require great wealth... and it is not an exact science," he said of the pre-sale estimates.

Sculpture has been especially strong in recent years, and Wednesday's sale bore that out, with sculpture accounting for three of four records broken on the night.