diff --git a/auth/mnet/auth.php b/auth/mnet/auth.php
index b3b22f534b1..160adfdb682 100644
--- a/auth/mnet/auth.php
+++ b/auth/mnet/auth.php
@@ -716,9 +716,7 @@ class auth_plugin_mnet extends auth_plugin_base {
 
         foreach($superArray as $subArray) {
             $subArray = array_values($subArray);
-            $instring = "('".implode("', '",$subArray)."')";
-            $query = "select id, session_id, username from {mnet_session} where username in $instring";
-            $results = $DB->get_records_sql($query);
+            $results = $DB->get_records_list('mnet_session', 'username', $subArray, '', 'id, session_id, username');
 
             if ($results == false) {
                 // We seem to have a username that breaks our query: