ajax – Unable to parse JSON response from wp_send_json_success


Trying to do this the WordPress way: wp_send_json_success

PHP processing save_form return:

        $response = array( 'messages' => $message );
        wp_send_json_success( $response );

jQuery:

        $j.ajax({
            type: 'POST',
            url: ajax_url,
            data: {
                    action:         'save_form',
                    form_id:        $j('#form_id').val(),
                    full_name:      $j('#full_name').val(),
                    email:          $j('#email').val(),
                    signup_nonce:   $j('#signup_nonce').val()
                },
            success: function (response) {
                    console.log(response.messages);
                },
            error: function (response) { }
        });
        return false;

Response in the Inspector:

JSON:
success: true
data: Object { messages: "Enter a valid email address" }
    messages: "Enter a valid email address" 

but…

console.log(response.messages);

returns nothing.

What am I missing?

Thanks, Brad