A Pablo Picasso masterpiece of his “golden muse” is predicted to trigger a $120m (£100m)-plus bidding war between billionaire art collectors on Wednesday night, in the first big lot of an autumn auction season that is expected to sell more than $2.5bn (£2bn) of art.

The portrait Femme à la Montre (Woman with Watch) will be sold at auction by Sotheby’s in New York at 6pm local time, with a sales estimate in excess of $120m (£98m).

The 1932 painting of Picasso’s secret lover, Marie-Thérèse Walter, was created during the artist’s explosive “year of wonders” as he prepared for his first large-scale retrospective in Paris at the age of 50 and is highly sought after by collectors.

“Picasso is all about passion, but this specific passion [for watches] is one that is not generally known about,” said Simon Shaw, Sotheby’s vice-chair for global fine arts. “He was an incredibly stylish man, very interested in his sartorial identity, and a great connoisseur of watches. Even photos of him wearing his watches are prized by watch collectors.”

The portrait was bought in 1968 by Emily Fisher Landau, one of the greatest art collectors of the 20th century. She hung it above the mantelpiece in the living room of her New York apartment. By the time she died, aged 102, earlier this year, her art collection could have filled several museums.

She pledged almost 400 works to the Whitney Museum of American Art in 2010, where she had long been a trustee. A further 120 artworks are being sold by Sotheby’s in New York on Wednesday and Thursday this week with a combined sales price expected to top £500m. Also up for sale are works by Ed Ruscha, Jasper Johns, Cy Twombly, Andy Warhol and Mark Rothko.

The Fisher Landau sale kickstarts the autumn auction season, which is expected to include more than £2bn of art sold by the big three sales houses Sotheby’s, Christie’s and Phillips.

On Thursday, Christie’s will sell a large Claude Monet water lily painting that has been largely unseen by the public, having been owned by the same family for more than 50 years.

Le Bassin aux Nymphéas (Water Lily Pond) forms part of Monet’s famous water lilies series displayed in museums across the world. “With Monet, seemingly everything has already been seen,” said Max Carter, Christie’s vice-chair of 20th- and 21st-century art, said. “Le Bassin aux Nymphéas, which has never been exhibited or offered at auction, is, however, that rarest thing: a masterpiece rediscovered.”

Fisher Landau began collecting art in earnest in 1969 after armed burglars disguised as air-conditioning repairmen broke into her apartment and stole diamonds, emeralds, rubies and sapphires that had been gifts from her husband. Instead of replacing the jewellery, Fisher Landau decided to use the substantial insurance payout to buy paintings and sculptures.

“I was devastated, [but] I decided that I didn’t want the jewellery any more. I now had seed money for a collection,” she said in an interview for a Whitney catalogue of works she owned. “What I really wanted to buy was paintings, so probably the theft was one of the best things that ever happened to me.”