Last season, the Magpies were operating in the fourth tier of women's football and, after turning professional in the summer, drew the Women's Super League (WSL) outfit away in the fourth round of the competition.
Despite being beaten 5-0 at Leigh Sports Village, Langley says that the support her team were shown by more than 1,000 travelling fans was nothing short of superb.
"Firstly, it's a great experience to test ourselves against a WSL side but for us, the actual occasion, when you're walking out of the tunnel and you look opposite us and see a sea of black and white shirts, it was just incredible," she said.
"We are really proud to see so many Geordies come out and support the team. We understand the context, we understand the level Manchester United are operating. We are just six months into a full-time programme here at Newcastle in tier three so we have got a long way to go.
"It is keeping our feet right on the ground with that but making sure we are taking the lessons away from today to ensure we win the (FA Women's National League Northern Premier Division) league."
Manchester United may have won by five goals, but Langley was pleased with the way her side performed against a side two divisions above them.
"Liv Watt, I think she was fantastic," said the Newcastle boss. "I think she went toe-to-toe with their winger throughout the game. She was playing against Geyse for the first 60 minutes and then they swapped the winger and she was playing against (Melvine) Malard.
"It was a great effort from everybody but I think as a collective you saw the effort and I think we went toe-to-toe for the 30 minutes when we pressed them really well and we are really proud of that as well. It's just a great experience and it's something we'll learn from."
Since their reformation in 2018, Manchester United Women have risen through the ranks and are now one of the top sides in the country. That journey is something Langley wants to emulate, as Newcastle strive to get promoted from the third tier this term.
"We want to get from tier three to the Championship as quickly as possible," she said. "We want to impose ourselves on the Championship as quickly as we can so we are absolutely delighted in terms of the level we have shown today at times.
"Obviously, we would rather have more of the ball and we'd rather show what we can do with the ball. You don't get much time on the ball at all (at WSL level).
"There are players in our team - Emma Kelly, Amber (Stobbs) and a few others - that have played at that level already. I think they stood up and were brilliant leaders for the team today."
After the match, as the Magpies were applauding the travelling supporters, Manchester United manager Marc Skinner and his team also showed their respect for the Newcastle fans by clapping them.
Langley says that moment was "a touch of class" from Skinner and the Reds and is grateful for the way the hosts welcomed her team to Leigh Sports Village.
"I think respect is earned and that came from our performance but I think Marc and his team were really respectful," she said. "Credit to them. They understand where we are at.
"They have probably been in those shoes a few years ago so I think we are incredibly proud of that and yeah, I think our respect is equal to Manchester United. It was a great test."
Looking ahead, the Newcastle boss hopes her side can use the experience of the match, and the occasion, to catapult them towards achieving their ambitions.
"There are a lot of Geordies in our team who will have memories that they can take forever," she added. "They will always remember the experience of playing Manchester United away in the FA Cup.
"So definitely we just need to build on this and make more memories. We need to make sure that we are winning the league at the end of the season and that's inspiring us to do that."
