Ng, who endured an injury setback on the first day of pre-season, marked his return to form by scoring his first goal of the campaign as the Bluebirds built on their Carabao Cup triumph at Burnley earlier in the week.
Barry-Murphy said: “Perry had an interrupted pre-season. He was dealt a very unfortunate injury on the first day of pre-season.
“So, to battle back like he's done is great. He's a player that we value hugely.
“To see him score a goal of such importance for us in this game was brilliant.”
The result keeps Cardiff in fourth place in League One - behind Bradford City, Stevenage and Lincoln City
For long spells in Lancashire, Cardiff dominated possession but were made to wait until stoppage time before sealing the points with a penalty from substitute Yousef Salech.
Barry-Murphy admitted his side had to stay calm as Wigan sat deep and threatened to find a way back into the contest.
“It was quite a difficult game today,” he said.
“I think when you have so much control and so much possession you feel as if your dominance should be reflected on the scoreboard and I suppose while the game was at one-nil that wasn’t the case.
“We had to show a lot of nerve and game management to see the game through and in the end we got what we deserved.
“I was aware of the jeopardy in the game. I have a lot of respect for Wigan and I’m aware of how dangerous the strikers on the pitch could be.
“I was keen to create more chances and get those second and third goals. The longer the game goes on, the more I’m aware of what could happen.
“It was a hard game in terms of turning our dominance into goals against a team who defended so deep. I’m sure we’ll improve as the season progresses. We pushed forward to the end though and sealed it.”
Ng’s early cross had already played a part in Tuesday’s upset win at Burnley, and at the DW Stadium he again set the tone.
His first-half strike, arriving after Cardiff’s spell of pressure, rewarded the visitors’ fast start and gave them a platform to control the game.
“The game on Tuesday gave us a real confidence, and I think you saw that in our performance today,” said Ng.
“I thought we passed the ball really well, our press was fantastic again, and Wigan couldn’t really get to terms with it.
“It was a brilliant performance all round, and another good away win. We were trying to go for the second to calm down a little bit, but it didn’t come, so we kept controlling the ball.
“Our play was fantastic; I think we could have been a little bit more ruthless up there and created more chances, but we’ll take the three points anyway.”
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Salech’s late penalty underlined the depth in Cardiff’s squad, something Barry-Murphy believes will be vital across the campaign.
“Our bench is very beneficial to us. We've seen already this season how those coming on can make an impact,” he said.
“The goal at Wimbledon away in the last minute was created and scored by people who came off the bench.
“We saw it at Stockport too. Dylan [Lawlor] came off the bench, as did Isaak Davies and Ronan Kpakio, who provided the assist for Yousef Salech. All those players have a huge importance to us. It's such a long season.
“There's a real sense of togetherness in that dressing room amongst all of our players and that is reflected on the pitch.”
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