Never respond to a challenge from a competitor smaller than you.
Drawing attention to a smaller competitor makes them larger in the eyes of the public.
Conversely, if someone bigger than you is foolish enough to shine their spotlight on you, dance in it.
(Adapted from an article by Roy H. Williams, the Wizard of Ads. Roy teaches the art of persuasion at Wizard Academy, a non-traditional business school... a school for the imaginative, the courageous and the ambitious. You should visit.)