diff --git a/css/css-flexbox/dynamic-isize-change-ref.html b/css/css-flexbox/dynamic-isize-change-001-ref.html
similarity index 100%
rename from css/css-flexbox/dynamic-isize-change-ref.html
rename to css/css-flexbox/dynamic-isize-change-001-ref.html
diff --git a/css/css-flexbox/dynamic-isize-change.html b/css/css-flexbox/dynamic-isize-change-001.html
similarity index 94%
rename from css/css-flexbox/dynamic-isize-change.html
rename to css/css-flexbox/dynamic-isize-change-001.html
index 5d3bc99a322c29..cf4a0300439845 100644
--- a/css/css-flexbox/dynamic-isize-change.html
+++ b/css/css-flexbox/dynamic-isize-change-001.html
@@ -5,7 +5,7 @@
   <link rel="author" title="Ting-Yu Lin" href="mailto:tlin@mozilla.com">
   <link rel="author" title="Mozilla" href="https://www.mozilla.org/">
   <link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1686961">
-  <link rel="match" href="dynamic-isize-change-ref.html">
+  <link rel="match" href="dynamic-isize-change-001-ref.html">
 
   <style>
   #container {