Leeds fought back from 2-0 down to level at 2-2 through Calvert-Lewin and Nemcha before Phil Foden struck City's winner in injury-time.
Nmecha said afterwards: “It's really tough to take, but we've just got to take the positives and learn from the negatives. I think in the second half we were really good. We caused them massive problems.
“I think the manager read the game well. We changed formation and we went two up top and I think that really gave us the freedom to, if we were in trouble, to go a bit longer. And that, after a while, created some spaces in between the lines, which was really important.
“When you concede like that, there's always little things and we're getting to that stage where we have to get away from the unlucky and look more at that little, little details to end up getting more points.”
Calvert-Lewin also said: "I think we can be proud of how we performed in the second half, but then frustrated at the same time to work so hard to get ourselves in such a good position. 2-0 down at the Etihad, it's a long way back, but we did it. It was just a finishing touch today. They've got good players that ultimately punish us in one single moment.
"Everyone was aligned, particularly in that second half. The Etihad's a difficult place to go for anybody. So the first half was tough, but to come out the second half, we responded in the right way and we followed the manager's instruction and we all worked together to get ourselves back in the game.
"We're all fully committed to a difficult week ahead. They're home games which we truly believe we can win and we believe that we've got the quality. I think we're close, we've been close in many games but ultimately you have to turn those nearly moments into our favour and that's what you have to do to stay in this division."