diff --git a/mercurial/scmutil.py b/mercurial/scmutil.py
--- a/mercurial/scmutil.py
+++ b/mercurial/scmutil.py
@@ -1247,7 +1247,7 @@
             if filtername:
                 repo = repo.filtered(filtername)
             func(repo, tr)
-        newcat = '%2i-txnreport' % len(categories)
+        newcat = '%02i-txnreport' % len(categories)
         otr.addpostclose(newcat, wrapped)
         categories.append(newcat)
         return wrapped