Qatar's bid to win a historic first AFC Asian Cup title has been thrown into doubt on the eve of the final after the United Arab Emirates complained that two members of their squad are ineligible.
The Asian Football Confederation said it was reviewing the complaint, which relates to tournament top scorer Almoez Ali and Bassam Al-Rawi.
"The Asian Football Confederation has received a protest from the United Arab Emirates FA regarding the eligibility of two Qatar players," an AFC statement said.
"This protest will now be reviewed in line with the AFC regulations."
Qatar beat hosts the UAE 4-0 in the semi-final on Tuesday to advance to Friday's final with Japan. The UAE is one of four countries from the region which has engaged in a diplomatic boycott of Qatar.
Qatar have taken the tournament by storm so far. Having never before advanced beyond the quarter-finals, Felix Sanchez's side have reached the final with six wins out of six, scoring 16 goals and scoring none.
Ali has eight goals in six appearances, equalling the 23-year-old Asian Cup record of Ali Daei with a match to spare.
Speaking on Thursday, Sanchez challenged his players to finish the job and deliver history for their nation.
"This is definitely the most important game in Qatar's football history," Sanchez said in a press conference.
"We are now obviously at the stage of the tournament where the team is in a confident mood and looking forward to starting the game. Obviously if we win the trophy, it will be Qatar's biggest achievement in terms of football."
Friday's final pits them against the record four-time winners Japan, who have never lost an Asian Cup final.
Coach Hajime Moriyasu was on the pitch as a player when they won their first crown in 1992.
"Tomorrow as a team we would like to try to take the trophy back home, but I'm not too interested in what it means to me," the former midfielder said.
"I just want to celebrate the title with all the team and we will do our best in training as well."
Qatar's form at both ends of the pitch has been formidable, but Moriyasu is confident Japan can succeed by sticking to the formula which has also brought them six wins from six in this tournament.
"We are aware they are a very strong team, that they have scored 16 goals and kept clean sheets all the way through, but no matter how they play we will stay the same," he said. "We will analyse them and then we will express our best on the field.
"We are also a team that has reached the final, so I want the players to be confident because of that. We have been developing as a team throughout each game and I want us to show that development on the field tomorrow."