The stadium's capacity is now up to 54,000 after an extra 8,500 seats were added to Anfield's main stand.
“I think everywhere you go, when you are with England or you speak to foreign players, Anfield around the world is renowned for a huge atmosphere," Carragher told the Daily Mail.
“I speak to Thierry Henry doing Sky and he always talks about it. They always wish they had it at their own clubs and I think that says it all.
“The interesting one was Jose Mourinho. At Soccer Aid he was the manager for a charity game and he asked me how many more people were going to be at Anfield with the new stand.
“I told him it would be an extra seven or eight thousand and he was like 'that is massive'.
“So he's well aware of the atmosphere. But not just him, I think everybody is and going there when Liverpool are playing well on the front foot with the crowd behind you as well [will be tough].
“I know we've said it before and it's a cliche, but it's certainly true at Liverpool, [they are] the extra man – the 12th man."