O'Driscoll believes that his squad must use that disappointment as fuel to drive them forward against the Wallabies in the Sydney decider on Saturday, while focusing on the positives of an instant shot at redemption and a first series win since 1997.
He told BBC Sport: "It is important to be able to feel the disappointment. If you try to banish it immediately it will come back to you, and it still does at times throughout the day.
"You think about how the scenario could have been different, having the series in the bag rather than having to fight for it over again this weekend.
"But you have to shelve that and focus on the target. It is just one more 80 minutes this season, that is all that is asked of the squad. And that is the 80 minutes of our lives."
The 34-year-old looks likely to be made Lions captain for the deciding Test, following the withdrawal of skipper Sam Warburton through injury earlier this week.