diff --git a/Lib/asyncio/proactor_events.py b/Lib/asyncio/proactor_events.py
index 23545c9ee9d..a80876f366a 100644
--- a/Lib/asyncio/proactor_events.py
+++ b/Lib/asyncio/proactor_events.py
@@ -38,7 +38,7 @@ class _ProactorBasePipeTransport(transports._FlowControlMixin,
             self._server.attach(self)
         self._loop.call_soon(self._protocol.connection_made, self)
         if waiter is not None:
-            waiter.set_result(None)
+            self._loop.call_soon(waiter._set_result_unless_cancelled, None)
 
     def _set_extra(self, sock):
         self._extra['pipe'] = sock
diff --git a/Lib/asyncio/selector_events.py b/Lib/asyncio/selector_events.py
index 628efb750ca..2a170340b9e 100644
--- a/Lib/asyncio/selector_events.py
+++ b/Lib/asyncio/selector_events.py
@@ -481,7 +481,7 @@ class _SelectorSocketTransport(_SelectorTransport):
         self._loop.add_reader(self._sock_fd, self._read_ready)
         self._loop.call_soon(self._protocol.connection_made, self)
         if waiter is not None:
-            waiter.set_result(None)
+            self._loop.call_soon(waiter._set_result_unless_cancelled, None)
 
     def pause_reading(self):
         if self._closing: