diff --git a/core/src/main/scala/knobs/Pattern.scala b/core/src/main/scala/knobs/Pattern.scala
index f048617..92346ab 100644
--- a/core/src/main/scala/knobs/Pattern.scala
+++ b/core/src/main/scala/knobs/Pattern.scala
@@ -16,6 +16,9 @@
 //: ----------------------------------------------------------------------------
 package knobs
 
+import scalaz.std.string._
+import scalaz.syntax.equal._
+
 /**
   * A pattern that matches a `Name` either exactly or as a prefix.
   */
@@ -25,8 +28,8 @@ sealed trait Pattern {
     case Prefix(s) => Prefix(pfx ++ s)
   }
   final def matches(n: Name): Boolean = this match {
-    case Exact(s) => s == n
-    case Prefix(s) => n startsWith n
+    case Exact(s) => s === n
+    case Prefix(s) => n startsWith s
   }
 }
 
diff --git a/core/src/test/scala/knobs/Test.scala b/core/src/test/scala/knobs/Test.scala
index 18baaf8..1ed309d 100644
--- a/core/src/test/scala/knobs/Test.scala
+++ b/core/src/test/scala/knobs/Test.scala
@@ -79,6 +79,16 @@ object Test extends Properties("Knobs") {
       cfg.lookup[String]("path.separator").map(_.isDefined)
     }
 
+  lazy val propertiesSubconfigTest: Task[Prop] =
+    withLoad(List(Required(SysPropsResource(Prefix("user"))))) { cfg =>
+      cfg.subconfig("user").lookup[String]("name").map(_.isDefined)
+    }
+
+  lazy val propertiesNegativeTest: Task[Prop] =
+    withLoad(List(Required(SysPropsResource(Prefix("user"))))) { cfg =>
+      cfg.lookup[String]("path.separator").map(_.isEmpty)
+    }
+
   lazy val fallbackTest: Task[Prop] =
     withLoad(List(Required(
       ClassPathResource("foobar.cfg") or
@@ -122,6 +132,10 @@ object Test extends Properties("Knobs") {
 
   property("load-system-properties") = loadPropertiesTest.unsafePerformSync
 
+  property("system-properties-negative") = propertiesNegativeTest.unsafePerformSync
+
+  property("system-properties-subconfig") = propertiesSubconfigTest.unsafePerformSync
+
   property("load-fallback-chain") = fallbackTest.unsafePerformSync
 
   property("fallback-chain-errors") = fallbackErrorTest.unsafePerformSync