The crucial moment of occurred with Ireland leading 13-9 in the 50th minute when Wales captain Matthew Rees took a quick lineout. Phillips took the ball and scampered away to score in the corner.
But TV replays showed that Rees had taken the lineout with a different ball to that kicked out of play by Ireland replacement Jonathan Sexton, something which is not allowed under IRB regulation 19.2.
Referee Jonathan Kaplan asked his assistant, Peter Allan of Scotland, whether the ball used was the same as that which left the field and, when he answered in the affirmative, the try was awarded.
O'Driscoll, who had claimed the first score of the game to level Ian Smith's championship record of 24 tries, said: "I didn't see it myself but when half your team saying it you take their word for it.
"I tried to relate that to Jonathan Kaplan and the touch judge and they were having none of it and it's really frustrating for such an incident to have a huge bearing on the game.
"I actually didn't (ask Kaplan to use the video official). When I went over to him he was pushing everyone away and I told him I was captain and he said that was fine but he wanted to talk to his touch judge.
"So I stood there and before anything else could be said he awarded the try.
"I did mention it to him a few minutes later after I had seen it on the TV and I told him that it was a massive momentum swinger and that it had had a huge bearing on the game, but he just shrugged that off."
When asked if he would be embarrassed if he had made an error in the manner of that made by the officials, he added: "If I was wrong I would personally be embarrassed, especially if you have the services there to cover all bases.
"Games hang in the balance on decisions, everyone is human and wrong calls are made sometimes, but some are unforgivable."