diff --git a/cake/libs/set.php b/cake/libs/set.php
index 8cf170b62..e12c877d4 100644
--- a/cake/libs/set.php
+++ b/cake/libs/set.php
@@ -487,6 +487,9 @@ class Set extends Object {
 				continue;
 			}
 			list(,$key,$op,$expected) = $match;
+			if (!isset($data[$key])) {
+				return false;
+			}
 			$val = $data[$key];
 			if ($op == '=' &&  $val != $expected) {
 				return false;
diff --git a/cake/tests/cases/libs/set.test.php b/cake/tests/cases/libs/set.test.php
index a5404e98b..ffc6172c9 100644
--- a/cake/tests/cases/libs/set.test.php
+++ b/cake/tests/cases/libs/set.test.php
@@ -470,6 +470,13 @@ class SetTest extends UnitTestCase {
 						'text' => 'Comment 5',
 					),
 				),
+			),
+			array(
+				'Article' => array(
+					'id' => 3,
+					'name' => 'Article 3',
+				),
+				'Comment' => array(),
 			)
 		);