Barry-Murphy also took the unusual step of substituting a substitute during the game against Reading.
Having made numerous attacking changes to help Cardiff come from behind to lead 2-1, the Irishman felt he needed to bolster his defence in the closing stages.
So 11 minutes after bringing on Cian Ashford, Barry-Murphy replaced the young forward with full-back Perry Ng.
"I didn't like it [having to make the change]. We'd made all of our changes to try and win the game," Barry-Murphy said.
"The game was chaos and we have an obligation to try and win the game to be at the top of the table.
"For me, it just looked inevitable with all those attacking players on the pitch that we were going to concede chances and obviously Yousef [Salech] could have come off, but they [Reading] were so dangerous with their set-pieces, free-kicks on corners that, for us, that would have been a huge problem.
"At that point, I made a decision that I thought it was best for us to win the game. Cian was the victim of being taken off. It's not something that I enjoy based on the value we hold Cian in."
