To earn this achievement, you must defeat your opponent by getting a Blackjack on your first turn against your opponent and he/she must go down to $0. The way I achieved this was by betting $1000 (the max hit
on the bet screen) each time with the idea that the computer would bet more that way. Then I just repeated this again and again. If I didn't get a Blackjack I would lose on purpose and try again. I achieved this on the second opponent, but the first hand. Good luck!