If only one search result

I am trying to get my wordpress blog to go directly to the post when a search returns only one result rather than the search results list page.

In other words I need to make the search engine go directly to the single.php file when there is only one search result. I have been looking through here and on google for hours now and I did not find any solutions except someone said that wordpress used to already do that.

Please help. Thank you in advance for your time…