"After scoring the first goal, I thought we would go and kill them off," he said.
"I thought we could score a few goals but then we started doing flicks and back heels, hitting balls into space where no-one was.
"We can play better than that but I am happy to get through it.
"It was really reckless football and it allowed Inter Milan to get a grip of the game.
"From the middle of the first half to the end of the first half they were the better team.
"We changed the system at half-time, closed the door on (Esteban) Cambiasso and we were a bit better in the second half.
"We played a team at its maximum - potential-wise with all the experience they have - and they played to their maximum.
"We can play better than that and I am sure we will be better in the next round."