"That was my first experience of a British derby game and all the atmosphere that goes with it - the manager gave me my chance and I didn't take it.
"I know that, and all I can do is take whatever comes my way on the chin and just move on to the next game.
"And all I can say is that it takes time to settle at a new club, and it's also taken me a while to get into the British game."
The 24 year old from Bunnell, Florida came on as a sub against Birmingham on the weekend. City lost 2 - 1 but Johnson looked more comfortable in the 15 mins he was on the pitch than he did that whole half at Swansea.
"It has taken me a while to get to the British game," he said. "I thought my pace would cause a factor but I struggled and took me longer than I thought to gel with the team. It's the real deal here.
"But there's definitely more to come from me and it's up to me and only me to make my mark. I will work hard in training- and the quality and competition here will only push me on."