I don't recommend the "have less scruples than the next guy" game. This is the sort of nonsense that was passed around in the 80s -- "business is war". There is an important difference between business and war: if you lose in war, you die. No second chances.
In business, if you are a tough but fair player, and you lose, you will be offered the chance to play again. If you compete in bad faith, you won't.