diff --git a/wp-includes/ms-functions.php b/wp-includes/ms-functions.php
index a56fcdc0fe..97a6fdbd38 100644
--- a/wp-includes/ms-functions.php
+++ b/wp-includes/ms-functions.php
@@ -1887,13 +1887,6 @@ function is_user_spammy( $username = 0 ) {
 	return false;
 }
 
-function login_spam_check( $user, $password ) {
-	if ( is_user_spammy( $user->ID ) )
-		return new WP_Error('invalid_username', __('<strong>ERROR</strong>: your account has been marked as a spammer.'));
-	return $user;
-}
-add_action( 'wp_authenticate_user', 'login_spam_check', 10, 2 );
-
 function update_blog_public( $old_value, $value ) {
 	global $wpdb;
 	do_action('update_blog_public');
diff --git a/wp-includes/user.php b/wp-includes/user.php
index 9bdf216d61..bc84943cda 100644
--- a/wp-includes/user.php
+++ b/wp-includes/user.php
@@ -83,20 +83,20 @@ function wp_authenticate_username_password($user, $username, $password) {
 		return $error;
 	}
 
-	$userdata = get_userdatabylogin($username);
+	$userdata = get_user_by('login', $username);
 
-	if ( !$userdata ) {
+	if ( !$userdata )
 		return new WP_Error('invalid_username', sprintf(__('<strong>ERROR</strong>: Invalid username. <a href="%s" title="Password Lost and Found">Lost your password</a>?'), site_url('wp-login.php?action=lostpassword', 'login')));
-	}
+
+	if ( is_multisite() && (1 == $userdata->spam) )
+		return new WP_Error('invalid_username', __('<strong>ERROR</strong>: Your account has been marked as a spammer.'));
 
 	$userdata = apply_filters('wp_authenticate_user', $userdata, $password);
-	if ( is_wp_error($userdata) ) {
+	if ( is_wp_error($userdata) )
 		return $userdata;
-	}
 
-	if ( !wp_check_password($password, $userdata->user_pass, $userdata->ID) ) {
+	if ( !wp_check_password($password, $userdata->user_pass, $userdata->ID) )
 		return new WP_Error('incorrect_password', sprintf(__('<strong>ERROR</strong>: Incorrect password. <a href="%s" title="Password Lost and Found">Lost your password</a>?'), site_url('wp-login.php?action=lostpassword', 'login')));
-	}
 
 	$user =  new WP_User($userdata->ID);
 	return $user;