Sir Alex Ferguson has predicted an end to Spain's recent dominance on the European stage, claiming that the diminishing qualities of Lionel Messi and Cristiano Ronaldo will see the top clubs struggle.
Barcelona and Real Madrid, boosted by Messi and Ronaldo in their ranks, have won each of the last three Champions League crowns between them and are on course for another success this term.
Two of the last three finals have been all-Spanish affairs, meanwhile, with Atletico Madrid falling just short on two occasions, but Ferguson expects to see things change in the coming years.
"I think success is cyclical," he told ESPN. "If you think about the '90s, it was AC Milan. In the '70s, Ajax; and Bayern Munich in the '80s; Liverpool, in the '90s; Italy, AC Milan; then England had a great spell with three teams about six years ago all in the semi-final. [Man United] were in three finals in four years.
"[Now] the domain is in Spain. There's no question about that. The same question could be asked about why are the German teams, why are Bayern Munich not winning the Champions League? Why are the Italians not winning it? Why are the French not winning it? And why are the English not winning it?
"I think the moment, the cycle is with the Spanish teams. They're the best, and that's why they're winning it. But that will change, that can change. You know, [Cristiano] Ronaldo will get older, [Lionel] Messi will get older. Can they replace these players? And I think the cycle will change."
Spain have three representatives in the last eight of this season's Champions League - more than any other nation.
Germany
Switzerland
Hungary
Scotland
Spain
Italy
Croatia
Albania
England
Denmark
Slovenia
Serbia
Austria
France
Netherlands
Poland
Romania
Belgium
Slovakia
Ukraine
Portugal
Turkey
Georgia
Czech Republic