Canny Lorenz Denney sold his house in Brighton for £615,000 on the internet after challenging three estate agents.

The semi-detached, eight-bedroom Edwardian pile overlooking Preston Park was sold to a couple based in New York who surfed the net to find a home. Fine art restorer Mr Denney, 52, bought the property in Preston Park Avenue in January last year for £275,000.

He has spent an estimated £150,000 overseeing restoration work by a team of builders. To get a quick sale, he invited three estate agents round at the same time and told them to "go and perform" for their commission. But even Mr Denney was surprised by the speed of the sale, the power of the internet and Brighton's soaring property prices.

When Mr Denney met the three agents he told them to write down their own valuation, without conferring, and the minimum and maximum prices he ought to accept. No For Sale boards were to be put outside and there was to be no advertising in newspapers or agents' windows for the first three weeks. The company which sent round the most suitable clients from its existing base would get the sole agency if no sale had been completed.

Mr Denney added: "They did not at first want to go along with idea of secret paper bids. Strangely enough, they were all very close to each other. I sent them away and they began to send clients round. I wanted to see who had the best punters and I wanted them to earn their money.

"Then I had a call from Mishon MacKay estate agents, who said they had a client in America who was flying over specifically to view the property. As the couple were coming over from America, I did not accept any bids in the meantime from anyone else."

The property was put on the market on March 17 and seen by its eventual buyers on the internet a few days later. They arrived to view it on April 3 and the sale was completed by April 28. It has all been completed so quickly Mr Denney is having to rent his own house from the buyers while he sorts out a move to another property in Dyke Road, Hove.

Mr Denney said: "I never thought of selling on the internet and I made no stipulation as to whether the property could be sold via the internet. It just did not occur to me. I am amazed everything has happened so quickly and efficiently."

Purchaser Joanna Weeks, who is returning to live in Brighton with her two children and her husband Gareth Baker, is delighted with her new home. Speaking from New York, she said: "Properties are bought and sold on the internet in America and there is nothing unusual about such a sale in the States."

Graham Farthing of Mishon MacKay said of the three-way challenge: "It was a rather unusual way of doing things. More and more houses are being sold via the internet. It all went through very smoothly. This is our first transatlantic sale of a house in Brighton via the internet."