diff --git a/src/filepath.c b/src/filepath.c
index 929fa56..7a5dae4 100644
--- a/src/filepath.c
+++ b/src/filepath.c
@@ -3626,7 +3626,7 @@
 	else if (path_end >= path + wildoff
 			 && (vim_strchr((char_u *)"*?[{~$", *path_end) != NULL
 			     || (!p_fic && (flags & EW_ICASE)
-					     && isalpha(PTR2CHAR(path_end)))))
+					  && vim_isalpha(PTR2CHAR(path_end)))))
 	    e = p;
 	if (has_mbyte)
 	{