diff --git a/src/nvim/insexpand.c b/src/nvim/insexpand.c
index 8625c0c1ca..cd5945731d 100644
--- a/src/nvim/insexpand.c
+++ b/src/nvim/insexpand.c
@@ -3147,7 +3147,15 @@ void f_complete_match(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
     char *cur_end = before_cursor + (int)strlen(before_cursor);
 
     while (*p != NUL) {
-      size_t len = copy_option_part(&p, part, MAXPATHL, ",");
+      size_t len = 0;
+      if (*p == ',' && *(p + 1) == ' ' && (*(p + 2) == ',' || *(p + 2) == NUL)) {
+        part[0] = ' ';
+        len = 1;
+        p++;
+      } else {
+        len = copy_option_part(&p, part, MAXPATHL, ",");
+      }
+
       if (len > 0 && (int)len <= col) {
         if (strncmp(cur_end - len, part, len) == 0) {
           int bytepos = col - (int)len;
diff --git a/test/old/testdir/test_ins_complete.vim b/test/old/testdir/test_ins_complete.vim
index 7d2288d97b..9ca8d1661a 100644
--- a/test/old/testdir/test_ins_complete.vim
+++ b/test/old/testdir/test_ins_complete.vim
@@ -3775,6 +3775,10 @@ func Test_complete_match()
   call feedkeys("Sabc, \<ESC>:let g:result=complete_match()\<CR>", 'tx')
   call assert_equal([[4, ',']], g:result)
 
+  set ise=\ ,=
+  call feedkeys("Sif true  \<ESC>:let g:result=complete_match()\<CR>", 'tx')
+  call assert_equal([[8, ' ']], g:result)
+
   bw!
   unlet g:result
   set isexpand&