The Tractor Boys were hammered 6-0 at Portman Road on Sunday night.
McKenna said afterwards: "Painful game for us. Beaten by a world-class side and they were too good for us. Positives the early parts of the game, but after the first goal they hit top form and top confidence - we weren’t able to find a response.
"They were outstanding and when that’s the case the gulf between us was too much on the day. Once they got the first goal they played really well, our confidence did drop and they caused us a lot of promise individually.
"The players showed some good character in the last 25 minutes. In a difficult moment in the last 20 minutes they regrouped well. We had to take our medicine and work hard to stop Man City."
On the Ipswich fans, he stated: “The supporters were fantastic as well. They were outstanding, and we are so grateful for the reception at the end - they know how hard we are working.
“The payers are working hard and they know we have climbed a mountain really quickly. There is going to be some difficult days are we don’t use that as an excuse.
"We are grateful for the way they stuck with us. On Monday we get the group in, and we need to analyse the things we need to do better and then it is on to Liverpool.
"Liverpool away is as good as what's out there.”