If you play aggressively against someone who knows the matchup (Disregarding spamming 66B, 66A, ag:A, most safe moves etc) you will be on the losing battle. A different type of aggressiveness would be punishing the ever daylights out of your opponent when they mess up, and it has happened to me countless times when I get a little over-zealous.
But if you punish the opponent a lot, in a way you're psychologically breaking them, which will eventually lead to them being more conservative so you can control the pace of battle how ever you want. Granted a fair few of the high level Nightmare's play that way. Just my piece!