diff --git a/mercurial/patch.py b/mercurial/patch.py
--- a/mercurial/patch.py
+++ b/mercurial/patch.py
@@ -1529,6 +1529,8 @@ def trydiff(repo, revs, ctx1, ctx2, modi
                 yield text
 
 def diffstatdata(lines):
+    diffre = re.compile('^diff .*-r [a-z0-9]+\s(.*)$')
+
     filename, adds, removes = None, 0, 0
     for line in lines:
         if line.startswith('diff'):
@@ -1539,9 +1541,9 @@ def diffstatdata(lines):
             adds, removes = 0, 0
             if line.startswith('diff --git'):
                 filename = gitre.search(line).group(1)
-            else:
+            elif line.startswith('diff -r'):
                 # format: "diff -r ... -r ... filename"
-                filename = line.split(None, 5)[-1]
+                filename = diffre.search(line).group(1)
         elif line.startswith('+') and not line.startswith('+++'):
             adds += 1
         elif line.startswith('-') and not line.startswith('---'):
diff --git a/tests/test-diffstat.t b/tests/test-diffstat.t
--- a/tests/test-diffstat.t
+++ b/tests/test-diffstat.t
@@ -46,3 +46,20 @@ Binary git diffstat:
    b |  Bin 
    1 files changed, 0 insertions(+), 0 deletions(-)
 
+  $ hg ci -m createb
+
+  $ printf '\0' > "file with spaces"
+  $ hg add "file with spaces"
+
+Filename with spaces diffstat:
+
+  $ hg diff --stat
+   file with spaces |    0 
+   1 files changed, 0 insertions(+), 0 deletions(-)
+
+Filename with spaces git diffstat:
+
+  $ hg diff --stat --git
+   file with spaces |  Bin 
+   1 files changed, 0 insertions(+), 0 deletions(-)
+