Many place the Liverpool sides of 1979 and 1984 among the greatest ever to grace a football pitch - but a man who played in both claims the current Barcelona team should now be regarded as the best in history.
Graeme Souness today declared that Pep Guardiola's Champions League finalists are the best team ever - more impressive even than Brazil's 1970 World Cup winning side.
"I think they're the best side ever and that, in Lionel Messi, they have got the best player ever," explained Souness.
"It's what you dream about. Everyone has come up with a plan to beat this team. There isn't one. What makes them so special is that they have players who, no matter what you do to try to nullify them, always come up with an answer."
Barcelona face Manchester United at Wembley on Saturday, with both clubs hoping to claim a fourth European Cup.
Souness believes Messi will be the difference.
"I don't think you can mark him," said the 58-year-old. "Maybe 25 years ago, you could put someone physical there and then when he gets a yellow card, find someone else.
"You can't do that anymore. He has got such quick feet that the ball seems to be a piece of elastic. And that's when he's sprinting."