"I think it was a month ago when he arrived," he told Sky. "In that month a lot has changed. I think he has already improved us a lot. A lot of things have changed but we already look forward to the future."
Despite defeat to Crystal Palace the Reds keeper is optimistic about the big game against City.
"It is a huge fixture and we look forward to that one. After the international duty we will make sure we prepare ourselves the best we can."