diff --git a/system/database/DB_query_builder.php b/system/database/DB_query_builder.php
index 68df309..b46730e 100644
--- a/system/database/DB_query_builder.php
+++ b/system/database/DB_query_builder.php
@@ -552,9 +552,9 @@
 			$cond = ' ON '.$newcond;
 		}
 		// Split apart the condition and protect the identifiers
-		elseif ($escape === TRUE && preg_match("/(.*)([\[\]\w\.'-]+)(\s*[^\"\[`'\w]+\s*)(.+)/i", $cond, $match))
+		elseif ($escape === TRUE && preg_match("/([\[\]\w\.'-]+)(\s*[^\"\[`'\w]+\s*)(.+)/i", $cond, $match))
 		{
-			$cond = ' ON '.$match[1].$this->protect_identifiers($match[2]).$match[3].$this->protect_identifiers($match[4]);
+			$cond = ' ON '.$this->protect_identifiers($match[1]).$match[2].$this->protect_identifiers($match[3]);
 		}
 		elseif ( ! $this->_has_operator($cond))
 		{