The Bluebirds crashed to a 3-1 defeat at Blackpool at the weekend, meaning they have lost five times in their last eight matches in all competitions.
They remain in the League One play-off places - in fourth spot - but only a point now separates them from seventh-placed Wimbledon.
The defeat meant back-to-back league losses for the first time this season, following their defeat at Bolton and their current form contrasts sharply to their early season success.
It was inevitable that Cardiff would be unable to maintain their momentum of August and September – when they went through their opening 10 matches unbeaten in all competitions.
But their recent form has left Barry-Murphy frustrated and he admitted: "The way that we play and the way we attack is not an excuse for us to defend the moments we had to defend in the manner we did.
"We've got to be as disciplined a team in defence as we are in attack and we weren't.
"It wasn't good enough – we have to swallow that today, accept it, feel the pain of it and come back stronger and be better."
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A clinical double from Ashley Fletcher and a late strike from Tom Bloxham handed the Seasiders back-to-back League One wins for the first time this season, while Yousef Salech’s stoppage-time consolation offered little comfort for the Bluebirds.
The Cardiff boss cut a dejected figure after watching his team fail to make the most of their chances in a game that could have gone either way before Blackpool’s ruthlessness in the final third made the difference.
Barry-Murphy said: “We have to stay disciplined throughout the course of the game.
“If the score says at 2-0 and we score that goal, we have the chance to salvage an equaliser.
“But to give away the third goal in the manner that we did is a real lesson. It's important we learn that lesson very quickly.”
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Salech’s late strike deep into added time provided a minor consolation, but by then the outcome had long been decided.
Barry-Murphy was quick to acknowledge the effort of the Cardiff fans who had travelled in numbers, expressing regret that his side could not repay their support with a result.
“You have to feel disappointed for so many of our supporters who came in such numbers and backed us throughout,” he said.
“Our support throughout the course of the game was exceptional. I'm just very disappointed we couldn't give them the result they wanted.”
The defeat leaves Cardiff searching for consistency after what has been a mixed run of performances in recent weeks.
While there were flashes of creativity and commitment, lapses in concentration at crucial moments once again proved costly — something Barry-Murphy says must change quickly if his side are to climb the table.
He stressed the importance of responding in the right way, both mentally and tactically, as the Bluebirds prepare for a crucial run of fixtures.
“We have to take responsibility,” he added. “Games like this hurt, but the reaction to them defines you. We’ll analyse where we fell short and make sure we respond.”
