Real Madrid have written to Spain's soccer federation (RFEF) to oppose La Liga's plans to play Villarreal's upcoming home match with Atletico Madrid in Miami, an RFEF spokesman said on Tuesday.
In the letter, Real complained that playing the proposed match "affects the integrity and fairness of the competition".
Real Madrid did not immediately respond to a request to comment, while La Liga declined to comment.
La Liga signed a 15-year deal with entertainment company Relevent in 2018 to promote Spanish soccer in North America, which included hosting one game per season stateside.
Its plan to play Girona's match with Barcelona in Miami last January fell through after Barca withdrew from the proposal, citing a lack of institutional support.
Yet the league has applied to hold the Dec. 6 game between Villarreal and Atletico in Miami, although RFEF president Luis Rubiales has said his organisation, which would have to agree to the move, continues to oppose playing league games abroad.
The RFEF announced on Monday that the Spanish Super Cup will be held in January 2020 in Saudi Arabia, but Rubiales said no other Spanish soccer competitions could be played outside Spain.
"Only the Super Cup can leave Spain, games in domestic competition cannot leave our borders," he said.
On Thursday, a commercial court in Madrid will hear a case brought by La Liga against the federation over its opposition to playing regular season games abroad.