O'Gara, 28, a midweek tourist in 2001, is expected to make his Lions Test debut against the All Blacks this weekend, whether as a starter or off the bench, as both Jonny Wilkinson (neck/shoulder) and Charlie Hodgson (concussion) are suffering from injuries.
The Corkman has made only two starts on the 2005 tour, against Bay of Plenty and Southland, and has been admittedly "annoyed" since missing two tackles in the Rotorua tour opener against Bay last month.
"I missed two tackles against Bay of Plenty and I was disappointed with that. Ever since then, there were defensive question marks and that kind of annoyed me.
"It has been frustrating but it's frustrating for other players too. The most important thing is to get game-time and prove what you can do and that's been the case since that game."
Meanwhile, England and Lions prop Graham Rowntree has been cleared of any wrong-doing by an independent match commissioner in yesterday's 17-13 defeat of Auckland.
Lions coach Sir Clive Woodward cancelled the tourists' training session earlier today due to a lengthening injury list.
The 2003 World Cup-winning coach, who names the Lions' third Test line-up on Saturday, said: "If we have a good night tonight (Wednesday) and we get all these players back in the morning, we should be able to train full-on tomorrow.
"As for Graham (Rowntree), I was obviously pleased that he was completely cleared of the incident he was cited for.
"It is the first time he has ever been cited, which clearly was a large factor in the outcome. He has got a totally unblemished record over a long period of playing rugby at the very top level in the front row."