diff --git a/lib/smtp.js b/lib/smtp.js
index 4d88fb9..67b0050 100644
--- a/lib/smtp.js
+++ b/lib/smtp.js
@@ -243,7 +243,8 @@ Client.prototype.setLogin = function(username, password) {
 };
 
 Client.prototype.smtpAUTH = function(next, mechanisms) {
-  var names = mechanisms.toUpperCase().split(/\s+/),
+  var self = this,
+      names = mechanisms.toUpperCase().split(/\s+/),
       method;
 
   if (!this.username)