"There are very thin dividing lines between success and failure," said Johnson.
"If that had gone in, I would have fancied our chances in extra-time, although to be fair to Mark he thought he was just offside."
What did wind up Johnson up was his side's stand-offish attitude during a first-half Man City dominated completely.
"I had a go at the players at half-time because I felt they were being a bit posy," he said.
"It was as though they wanted to look like Premiership players. They weren't anywhere near angry enough.
"In the end, I thought we gave a good account of ourselves. If Sven says we did well, he means it. He is not the type of bloke to say that if he didn't."
Eriksson was happy to be in round 3
"I am relieved to be through," confirmed the former England coach.
"We should have finished it much more easily. We had five or six good opportunities to score in the first-half alone.
"But the rules of football are always the same. If you don't take your chances, eventually you will suffer."