Uefa president Aleksander Ceferin says the "regrettable" decision to allow two European league matches to be played abroad is "exceptional" and insists it "will not set a precedent".
La Liga clubs Villarreal and Barcelona are now set to face each other in Miami in December in what would be the first European league fixture to be played abroad.
Then in February, AC Milan's Italian Serie A match against Como will be played in Perth, Australia.
Uefa, European football's governing body, has stressed its "clear opposition" to the plans, but "reluctantly" approved them because there is no legal framework to stop it.
"League matches should be played on home soil; anything else would disenfranchise loyal match-going fans and potentially introduce distortive elements in competitions," said Ceferin.
"Our consultation confirmed the breadth of these concerns. I would like to thank the 55 national associations for their constructive and responsible engagement on such a sensitive issue.
"While it is regrettable to have to let these two games go ahead, this decision is exceptional and shall not be seen as setting a precedent. Our commitment is clear: to protect the integrity of national leagues and ensure that football remains anchored in its home environment."
