Want to redirect if search query match exact title of any post

I am using WordPress 3.3.1 and new to this system. I want to redirect the search query to the post if query exactly matches post title of some post.
I also want it to run before any search query function and hooks or filter. I have made some changes in query.php in include folder

$search .= "{$searchand}(($wpdb->posts.post_title LIKE '{$n}{$term}{$n}'))";

and wrote some plugin function like this:

add_action('template_redirect', 'single_result');
function single_result() {
    if (is_search()) {
        global $wp_query;
        if ($wp_query->post_count == 1) {
            wp_redirect( get_permalink( $wp_query->posts['0']->ID ) );
        }
    }
}

I have also some function that need to run just after this search query and has “get_header” hooks. So far the search query match and redirect is not matching and returning as aspected. It most of the time slips out and don’t redirect perfectly. I want search and redirect to be very perfect.
Any help will be highly appreciated and thankful. Thank you.