The kick was a personal moment of catharsis for Halfpenny as it was a his penalty which fell short of the posts in Wales' World Cup semi-final four minutes from time, allowing France to cling on and reach the final.
February's successful effort set the Red Dragons on their way to a third RBS 6 Nations Grand Slam in eight years and when Halfpenny lines up for Cardiff Blues' Heineken Cup quarter-final against Leinster he will do so in the belief that victory is, again, possible.
It will be a tough assignment for Cardiff as they have lost their last three PRO12 matches and are without Jamie Roberts, who is sidelined for up to six months through injury.
Coupled with the fact they are playing the Heineken Cup champions means it could be backs to the wall for the Welsh side in Dublin but Halfpenny believes that's when they're at their peak.
"Everyone is writing us off but we have plenty of quality in this team and we're at our best under pressure," said Halfpenny.
"After the World Cup, everyone was so supportive but it didn't really help me move on. I always had it in my head, every single day.
"From that moment I said to myself that if I ever get another opportunity to kick a winning penalty for Wales, I want to nail it.
"I just practised and practised and practised, so when I kicked that one against Ireland, I was really proud, knowing how much work I'd put in since the miss against France.
"I'd set myself a goal and to achieve it was hugely satisfying. So much had gone into that moment and it was nerve-racking but it was one of the best feelings ever when I saw it go through.
"It was another high-pressure situation [against Ireland] but I'd been able to handle it and produce a positive outcome.
"Then the long-range kick against France at the Millennium Stadium [in Wales's last match of the Championship] really put it to bed once and for all. It was the same opposition so that was really important."