That sort of comment is ridiculous. Duncan made one error last night but apart from than he has been one of our best all season. This needs pressure and too comfortable shit is neo-liberalism ideology at its finest. There is little if any evidence to back up such claims in football or any other occupation. In fact there is a lot to suggest that pressure for positions can actually have the opposite effect whereby individuals start putting themselves before the best interests of the team.
Duncan fumbled a wet ball in slippery conditions - that is what happened. Keepers in the top leagues around the world have done just as bad and in a lot of cases worse than Duncan did last night. Did they stuff up because of no pressure for their position ? Of course not - and neither did Duncan.