Rounds

By default, there are two rounds of combat. However, the players have a choice from one to five rounds, as well as options for the time limit of each round. If the winning character retains all his or her health without the time limit expiring, the announcer will call, "Perfect!" If the winning character is near knock out, the announcer will call, "Great!" It is possible that both characters can be knocked out simultaneously, and the announcer will call "Double K.O." If the time limit for the round expires, the character with more health will be declared the winner. If both players have equal health remaining, the round will be a draw. In other cases, the announcer will call "K.O." when one character is triumphant or "Double K.O." when both opponents have been knocked out simultaneously. In Arcade Mode, if a double K.O. occurs in the final round, the CPU automatically wins and the game will end unless desired to continue.

http://en.wikipedia.org/wiki/Tekken