diff --git a/builtin/diff.c b/builtin/diff.c
index 1a1149eed4..5e7c6428c9 100644
--- a/builtin/diff.c
+++ b/builtin/diff.c
@@ -90,7 +90,8 @@ static int builtin_diff_b_f(struct rev_info *revs,
 		     blob[0]->mode, canon_mode(st.st_mode),
 		     &blob[0]->item->oid, &null_oid,
 		     1, 0,
-		     path, path);
+		     blob[0]->path ? blob[0]->path : path,
+		     path);
 	diffcore_std(&revs->diffopt);
 	diff_flush(&revs->diffopt);
 	return 0;
diff --git a/t/t4063-diff-blobs.sh b/t/t4063-diff-blobs.sh
index 80ce033ab6..bc69e26c52 100755
--- a/t/t4063-diff-blobs.sh
+++ b/t/t4063-diff-blobs.sh
@@ -81,11 +81,16 @@ test_expect_success 'diff blob against file' '
 test_expect_success 'index of blob-file diff' '
 	check_index $sha1_one $sha1_two
 '
-test_expect_failure 'blob-file diff uses filename as paths' '
+test_expect_success 'blob-file diff uses filename as paths' '
 	check_paths one two
 '
 test_expect_success FILEMODE 'blob-file diff shows mode change' '
 	check_mode 100644 100755
 '
 
+test_expect_success 'blob-file diff prefers filename to sha1' '
+	run_diff $sha1_one two &&
+	check_paths two two
+'
+
 test_done