diff --git a/src/dzitilesource.js b/src/dzitilesource.js
index 99dd92d1..5d00980f 100644
--- a/src/dzitilesource.js
+++ b/src/dzitilesource.js
@@ -139,7 +139,8 @@ $.extend( $.DziTileSource.prototype, $.TileSource.prototype, /** @lends OpenSead
         }
 
         if (url && !options.tilesUrl) {
-            options.tilesUrl = url.replace(/([^\/]+)\.(dzi|xml|js)(\?.*|$)/, '$1_files/');
+            options.tilesUrl = url.replace(
+                    /([^\/]+?)(\.(dzi|xml|js))?\/?(\?.*)?$/, '$1_files/');
 
             if (url.search(/\.(dzi|xml|js)\?/) != -1) {
                 options.queryParams = url.match(/\?.*/);
diff --git a/test/coverage.html b/test/coverage.html
index 15d3d490..bcf893ee 100644
--- a/test/coverage.html
+++ b/test/coverage.html
@@ -1,4 +1,4 @@
-﻿<!DOCTYPE html>
+<!DOCTYPE html>
 <html>
 <head>
     <meta charset="utf-8">
@@ -73,6 +73,7 @@
     <script src="/test/modules/tilecache.js"></script>
     <script src="/test/modules/referencestrip.js"></script>
     <script src="/test/modules/tilesource.js"></script>
+    <script src="/test/modules/dzitilesource.js"></script>
     <script src="/test/modules/tilesourcecollection.js"></script>
     <script src="/test/modules/spring.js"></script>
     <script src="/test/modules/rectangle.js"></script>
diff --git a/test/modules/dzitilesource.js b/test/modules/dzitilesource.js
new file mode 100644
index 00000000..fe4677a0
--- /dev/null
+++ b/test/modules/dzitilesource.js
@@ -0,0 +1,38 @@
+
+/*global module:true, test:true, equal:true, OpenSeadragon:true*/
+
+(function() {
+
+    module('DziTileSource', {
+        setup: function() {
+            testLog.reset();
+        }
+    });
+
+    function testImplicitTilesUrl(dziUrl, expected, msg) {
+        var source = new OpenSeadragon.DziTileSource();
+        var options = source.configure({
+            Image: {Size: {Width:0, Height: 0}}
+        }, dziUrl);
+        equal(options.tilesUrl, expected, msg);
+    }
+
+    test('test implicit tilesUrl guessed from dzi url', function() {
+        testImplicitTilesUrl(
+            '/path/my.dzi', '/path/my_files/',
+            'dzi extension should be stripped');
+        testImplicitTilesUrl(
+            '/path/my', '/path/my_files/',
+            'no extension should still produce _files path');
+        testImplicitTilesUrl(
+            '/my/', '/my_files/',
+            'no extension with trailing slash should preserve slash');
+        testImplicitTilesUrl(
+            'my.xml', 'my_files/',
+            'relative link should stay the same');
+        testImplicitTilesUrl(
+            '/p/foo.dzi?a=1&b=2', '/p/foo_files/',
+            'querystring in dzi url should be ignored');
+    });
+
+}());
diff --git a/test/test.html b/test/test.html
index d50e53eb..6a42284f 100644
--- a/test/test.html
+++ b/test/test.html
@@ -1,4 +1,4 @@
-﻿<!DOCTYPE html>
+<!DOCTYPE html>
 <html>
 <head>
     <meta charset="utf-8">
@@ -37,6 +37,7 @@
     <script src="/test/modules/tilecache.js"></script>
     <script src="/test/modules/referencestrip.js"></script>
     <script src="/test/modules/tilesource.js"></script>
+    <script src="/test/modules/dzitilesource.js"></script>
     <script src="/test/modules/tilesourcecollection.js"></script>
     <script src="/test/modules/spring.js"></script>
     <script src="/test/modules/rectangle.js"></script>
