diff --git a/IPython/core/pylabtools.py b/IPython/core/pylabtools.py
index 4423ed5..d42c088 100644
--- a/IPython/core/pylabtools.py
+++ b/IPython/core/pylabtools.py
@@ -310,12 +310,12 @@ def activate_matplotlib(backend):
     # magic of switch_backend().
     matplotlib.rcParams['backend'] = backend
 
-    import matplotlib.pyplot
-    matplotlib.pyplot.switch_backend(backend)
+    # Due to circular imports, pyplot may be only partially initialised
+    # when this function runs.
+    # So avoid needing matplotlib attribute-lookup to access pyplot.
+    from matplotlib import pyplot as plt
 
-    # This must be imported last in the matplotlib series, after
-    # backend/interactivity choices have been made
-    import matplotlib.pyplot as plt
+    plt.switch_backend(backend)
 
     plt.show._needmain = False
     # We need to detect at runtime whether show() is called by the user.
diff --git a/IPython/sphinxext/ipython_directive.py b/IPython/sphinxext/ipython_directive.py
index 60c1b51..0481624 100644
--- a/IPython/sphinxext/ipython_directive.py
+++ b/IPython/sphinxext/ipython_directive.py
@@ -585,7 +585,7 @@ class EmbeddedSphinxShell(object):
                 if self.warning_is_error:
                     raise RuntimeError('Non Expected warning in `{}` line {}'.format(filename, lineno))
 
-        self.cout.truncate(0)
+        self.clear_cout()
         return (ret, input_lines, processed_output,
                 is_doctest, decorator, image_file, image_directive)