Force virtualenv pip to be used

Sun Nov 6 05:17:16 EST 2016

Running Ubuntu 16.10 with Python 2.7.12+ (default one) and virtualenv
15.0.3 (`sudo -H pip install virtualenv`). What am I doing wrong?
 $ virtualenv a && . "$_"/bin/activate && pip --version
 New python executable in /tmp/a/bin/python
 Installing setuptools, pip, wheel...done.
 pip 9.0.0 from /usr/local/lib/python2.7/dist-packages (python 2.7)
 $ /tmp/a/bin/pip --version
 pip 9.0.0 from /usr/local/lib/python2.7/dist-packages (python 2.7)
 $ /tmp/a/bin/python -c 'from pip import __file__; print __file__'
 /usr/local/lib/python2.7/dist-packages/pip/__init__.pyc
PS: Running with regular Bash 4.3.46(1)-release in GNOME Terminal. When I
activate the virtualenv this appears in my env output: VIRTUAL_ENV=/tmp/a
PPS: Cross-posted [yesterday] http://stackoverflow.com/q/40438089