"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," UEFA president Aleksander Ceferin said in a statement.
UEFA made its ruling after Spain's LaLiga agreed to move a game scheduled for late December between champions Barcelona and Villarreal to Miami, Florida.
Italy's Serie A also decided to stage the encounter between AC Milan and Como on February 8th in Perth, Australia, to avoid a clash with the Winter Olympics opening ceremony at Milan's San Siro stadium.
But that sparked protests from European supporters groups who branded the moves "absurd, unaffordable, and environmentally irresponsible".
In its statement, UEFA said that it had "reiterated its clear opposition to domestic league matches being played outside their home country".
But despite "the widespread lack of support that had already been raised by fans, other leagues, clubs, players and European institutions", UEFA said that it had found no clear regulatory framework in FIFA's statutes that would allow it to oppose the moves.
"The UEFA Executive Committee has reluctantly taken the decision to approve, on an exceptional basis, the two requests referred to it," European football's governing body said in its statement.