Emiratis file complaint hours after losing semi-final, saying Qatar used ineligible players during the tournament.
Japan, Asia’s No 3 side, sit 43 places above their opponents and are the clear favourites for the trophy, especially after a commendable show in the 2018 World Cup.
For Qatar, the road to the final has not come without controversy.
Hosts UAE, along with Saudi Arabia, Bahrain and Egypt severed all diplomatic and economic ties with Doha, imposing a land, sea and air blockade on the Gulf nation in June 2017.
The team had to take a circuitous route via Kuwait lasting more than five hours to make an air journey that can be done directly in under an hour.
Playing against the backdrop of that regional political dispute and without any fans in the stands, Qatar beat Saudi Arabia 2-0 in a group match and then thrashed UAE 4-0 in a semi-final which saw shoes and bottles hurled at Qatari players.
Following the defeat, the UAE lodged a complaint with the Asian Football Confederation (AFC) over the eligibility of two of Qatar’s players.
But Qatar’s players, officials and fans are confident of putting those incidents behind them and bringing home the country’s maiden Asian Cup trophy.
“All the obstacles and the circumstances behind our participation in this competition have given our players more energy and motivation,” said Ali al-Salat, Qatar Football Association’s (QFA) media officer.
On the field, Qatar is yet to be beaten in the tournament and has not conceded a single goal in six matches.
With eight goals, 22-year-old Almoez Ali is the tournament’s top scorer, equalling the Asian Cup record.
“There are no words to describe what playing in the final means to me,” Qatar’s captain Hassan al-Haydos told reporters on the eve of the final. “It is definitely very important to us as a team.”
Qatar’s coach Felix Sanchez believes his players are ready for one final push that can land them the title.
“The players are determined to get the victory we want by putting in one more huge effort against Japan so that we can make the Qatari people happy once again and make history,” said Sanchez.
Qatar’s fans have been unable to attend the fixtures in the UAE because of the ongoing dispute. For them, however, the team reaching the final is a feat worth the tournament trophy itself.
“We are winners already by beating all these teams, including Saudi Arabia, UAE, Iraq and South Korea,” Ali, a 30-year-old Qatari engineer, told Al Jazeera.
In the capital Doha, preparations were in full swing before the final.
On Thursday, a grandstand was being mounted and beanbags, seating almost 750 people, were being placed for the screening of the final at Aspire Park.
A group of mothers huddled nearby, animatedly discussed the crowd’s behaviour from the semi-final.
Special TV screenings will also take place at different locations around the city, including Souq Waqif, Katara cultural village, as well as restaurants, malls and hotels.
“Personally it doesn’t matter if we get the trophy or not,” said Bassam Hamdaoui, a Tunisian expatriate. “They have already overcome the big challenge. This Asian Cup aptly illustrates the Gulf political situation.”
On Twitter, fan reaction is split between the two teams, according to an Al Jazeera poll.
Football analysts are expecting an “interesting tactical battle”.
“Qatar has already shown how capable they are at upping the gears when needed,” said Martin Lowe, an Asian football writer. “It will be a terrific game, which should showcase the very best of Asian football.”
Follow Saba Aziz on Twitter: @saba_aziz