"We came across a very organised French defence. We knew we would need a class performance from 1 to 15 and that didn't quite happen," O'Driscoll said.
"There wasn't enough of the performance we'd been talking about. When we had the ball we didn't do enough with it. The scoreline doesn't lie. France kept the scoreboard ticking over and it was a real sucker punch when they got their (first) try."
Admitting that his side's discipline had let them down at times during the game, O'Driscoll added: "If you don't play out of your skin against France, you come off second best. It's very disappointing and we're going to need a massive result against Argentina. I don't know what the permutations are, but we'll think about that tomorrow (Saturday).
"For the moment, we're just disappointed we didn't put in the performance that we'd been talking about all week.
"We have got to go out to win it and play a lot better than that. It's a big ask but stranger things have happened. You don't ever lose faith in what you're capable of, but so far we haven't produced that."