Simon Poulsen admits he is still haunted by the mistake which led to Denmark falling behind against Holland.
The full-back was largely responsible for the opening goal of the game, with his wayward header cannoning off the back off team-mate Daniel Agger and into the back of the net.
The defender was able to smile about the incident at the time, with the Danes hugely unfortunate to find themselves behind.
However, having seen the Dutch go on to grab a second in the Group E encounter, Poulsen is well aware that things could have been so different had his clearance gone according to plan.
"I have thought about it a thousand times," he said.
"Of course, I have tried to think about all the positive moments in the match, and I think the team and myself played a good first half.
"Yet the [own] goal keeps coming back.
"I have seen it on TV, and it's really unfortunate."
Meanwhile, Denmark saw Nicklas Bendtner sit out training again on Thursday as he continues to nurse a groin problem.
The Arsenal striker was forced off after an hour of the Holland clash and faces a race against time to prove his fitness ahead of a meeting with Cameroon on Saturday.