diff --git a/Lib/tarfile.py b/Lib/tarfile.py
--- a/Lib/tarfile.py
+++ b/Lib/tarfile.py
@@ -2417,17 +2417,17 @@ def is_tarfile(name):
     """
     try:
         t = open(name)
         t.close()
         return True
     except TarError:
         return False
 
-bltn_open = open
+bltn_open = _open
 open = TarFile.open
 
 
 def main():
     import argparse
 
     description = 'A simple command line interface for tarfile module.'
     parser = argparse.ArgumentParser(description=description)