diff --git a/src/pip/_internal/__init__.py b/src/pip/_internal/__init__.py
index 8c0e4c58..76e280e5 100755
--- a/src/pip/_internal/__init__.py
+++ b/src/pip/_internal/__init__.py
@@ -1,2 +1,3 @@
 #!/usr/bin/env python
 import pip._internal.utils.inject_securetransport  # noqa
+from pip._internal import main  # noqa
diff --git a/src/pip/_internal/main.py b/src/pip/_internal/main.py
index 1e922402..e52e04d8 100644
--- a/src/pip/_internal/main.py
+++ b/src/pip/_internal/main.py
@@ -45,3 +45,15 @@ def main(args=None):
     command = create_command(cmd_name, isolated=("--isolated" in cmd_args))
 
     return command.main(cmd_args)
+
+
+# Dark magic to make the main module itself callable.
+# This is needed to be able to use this pip in ensurepip of older Pythons
+# without patching all the Pythons.
+
+class _CallableModule(sys.modules[__name__].__class__):
+    def __call__(self, *args, **kwargs):
+        return main(*args, **kwargs)
+
+
+sys.modules[__name__].__class__ = _CallableModule