The Lions were defeated by the Brumbies when the pair met on June 18, but the Irishman believes that Tuesday's win has atoned for that defeat.
"We were pretty annoyed after last Tuesday against the Brumbies and were determined to put things right with a good performance," O'Brien told Sky Sports News.
"The main thing was to go out and work hard for each other, and not try and make it an individual thing. If the team plays well, then individuals can."
The second Test against Australia takes place on Saturday.