diff --git a/Lib/test/test_telnetlib.py b/Lib/test/test_telnetlib.py
index c8da421e46d..11e95e77b75 100644
--- a/Lib/test/test_telnetlib.py
+++ b/Lib/test/test_telnetlib.py
@@ -170,13 +170,14 @@ class ExpectAndReadTestCase(TestCase):
     def setUp(self):
         self.old_select = select.select
         select.select = mock_select
+        self.old_poll = False
         if hasattr(select, 'poll'):
             self.old_poll = select.poll
             select.poll = MockPoller
             MockPoller.test_case = self
 
     def tearDown(self):
-        if hasattr(select, 'poll'):
+        if self.old_poll:
             MockPoller.test_case = None
             select.poll = self.old_poll
         select.select = self.old_select
@@ -211,7 +212,8 @@ def test_read_until_with_select(self):
         """Use select.select() to implement telnet.read_until()."""
         want = [b'x' * 10, b'match', b'y' * 10]
         telnet = test_telnet(want, use_poll=False)
-        select.poll = lambda *_: self.fail('unexpected poll() call.')
+        if self.old_poll:
+            select.poll = lambda *_: self.fail('unexpected poll() call.')
         data = telnet.read_until(b'match')
         self.assertEqual(data, b''.join(want[:-1]))
 
@@ -429,7 +431,8 @@ def test_expect_with_select(self):
         """Use select.select() to implement telnet.expect()."""
         want = [b'x' * 10, b'match', b'y' * 10]
         telnet = test_telnet(want, use_poll=False)
-        select.poll = lambda *_: self.fail('unexpected poll() call.')
+        if self.old_poll:
+            select.poll = lambda *_: self.fail('unexpected poll() call.')
         (_,_,data) = telnet.expect([b'match'])
         self.assertEqual(data, b''.join(want[:-1]))