diff --git a/Lib/test/test_importlib/extension/test_loader.py b/Lib/test/test_importlib/extension/test_loader.py
index 5813ade..d82c805 100644
--- a/Lib/test/test_importlib/extension/test_loader.py
+++ b/Lib/test/test_importlib/extension/test_loader.py
@@ -177,6 +177,14 @@ class MultiPhaseExtensionModuleTests(abc.LoaderTests):
         self.assertEqual(module.__name__, 'pkg.' + self.name)
         self.assertEqual(module.str_const, 'something different')
 
+    def test_load_short_name(self):
+        '''Test loading module with a one-character name'''
+        module = self.load_module_by_name('x')
+        self.assertIsInstance(module, types.ModuleType)
+        self.assertEqual(module.__name__, 'x')
+        self.assertEqual(module.str_const, 'something different')
+        assert 'x' not in sys.modules
+
     def test_load_twice(self):
         '''Test that 2 loads result in 2 module objects'''
         module1 = self.load_module_by_name(self.name)
diff --git a/Modules/_testmultiphase.c b/Modules/_testmultiphase.c
index 0d50db2..7b98be2 100644
--- a/Modules/_testmultiphase.c
+++ b/Modules/_testmultiphase.c
@@ -321,6 +321,14 @@ PyInitU_eckzbwbhc6jpgzcx415x(PyObject *spec)
     return PyModuleDef_Init(&def_nonascii_kana);
 }
 
+/*** Module with a single-character name ***/
+
+PyMODINIT_FUNC
+PyInit_x(PyObject *spec)
+{
+    return PyModuleDef_Init(&main_def);
+}
+
 /**** Testing NULL slots ****/
 
 static PyModuleDef null_slots_def = TEST_MODULE_DEF(
diff --git a/Python/importdl.c b/Python/importdl.c
index 579d2c5..9e354dc 100644
--- a/Python/importdl.c
+++ b/Python/importdl.c
@@ -35,8 +35,10 @@ static const char *nonascii_prefix = "PyInitU";
 static PyObject *
 get_encoded_name(PyObject *name, const char **hook_prefix) {
     char *buf;
+    char c;
     PyObject *tmp;
     PyObject *encoded = NULL;
+    PyObject *modname = NULL;
     Py_ssize_t name_len, lastdot, i;
 
     /* Get the short name (substring after last dot) */
@@ -71,19 +73,25 @@ get_encoded_name(PyObject *name, const char **hook_prefix) {
         }
     }
 
-    buf = PyBytes_AS_STRING(encoded);
-    assert(Py_REFCNT(encoded) == 1);
+    /* Replace '-' by '_' */
+    modname = PyBytes_FromStringAndSize(NULL, PyBytes_GET_SIZE(encoded));
+    if (modname == NULL)
+        goto error;
     for (i = 0; i < PyBytes_GET_SIZE(encoded) + 1; i++) {
-        if (buf[i] == '-') {
-            buf[i] = '_';
+        c = PyBytes_AS_STRING(encoded)[i];
+        if (c == '-') {
+            c = '_';
         }
+        PyBytes_AS_STRING(modname)[i] = c;
     }
 
     Py_DECREF(name);
-    return encoded;
+    Py_DECREF(encoded);
+    return modname;
 error:
     Py_DECREF(name);
     Py_XDECREF(encoded);
+    Py_XDECREF(modname);
     return NULL;
 }