The USA led 10-6 going into the final day before Europe completed a remarkable comeback to win the cup 14 1/2 to 13 1/2.
Had Woods held on to his lead against Francesco Molinari then the cup would have ended as a draw, however Woods said that his head had gone after losing the hole to the Italian.
"It was already over. We came here as a team - this is a team event," said Woods.
"And the Cup was already being retained by Europe, so it was already over. You come here as a team and you win or lose as a team, and it's pointless to even finish.
"So 18 was just, hey, get this over with. Congratulations to the European team. They played fantastic and they deserve the cup."
Woods failed to win a match throughout the whole Ryder Cup.