And the 34-year-old has shown no signs of slowing down, kicking last-gasp drop-goals to beat Northampton and Castres already in the competition.
But with the Six Nations fast approaching, O'Connell has backed his club and international teammate to keep landing the blows when it really matters.
"You know in a game that if we are on the ropes you have a guy there that can pull it out of the fire for you and that actually wants to be in that position, that wants to have the clutch kick or to produce the play to win a game or a drop goal, as he has done in the past," O'Connell said.
"I think that's probably the big thing about him, his mental strength. It's brilliant.
"You want to have as many great players in your team as you can but then you want to have players that you know when they have a setback, they are going to come back stronger and harder than ever.
"Be that a setback in the middle of a game, or be that a setback career-wise with an injury or being dropped or whatever, you want guys that have that kind of mental toughness in your team, and that's what he has in abundance."