Emirates have been the surprise contender in the 2011 continental club championship, and the little Ras al Khaimah side hope to make an unexpected appearance in the knockout stages.
They are the first club outside their country's top flight to play in the Asian Champions League (ACL) and are the only UAE side with a chance to reach the last 16 as the final round is played today and tomorrow.
Emirates, however, face a significant challenge to become the first UAE side to advance out of the group stage since 2007. They must win away to Al Rayyan of Qatar tonight and Al Shabab of Saudi Arabia must lose away to Zob Ahan in Iran.
Also, Emirates will play without four of their preferred first XI, suspended for the match for accumulated cautions, among them their influential Algerian forward Hadj Bougueche.
They may also be missing their Moroccan striker Nabil Daoudi, who has been battling an injury. The two North Africans have produced five of the six goals Emirates have scored in the competition.
"We have suitable replacements," Ghazi Ghrairi, the Tunisian coach of Emirates, said yesterday at a press conference in Doha. "We are not worried that we can still surprise [Rayyan]."
He did not minimise the importance of the competition to his club.
"This is a very important event for us," he said. "This is Asia's top tournament. We want to do well."
When asked about the searing heat in Doha, where temperatures topped 47°C yesterday afternoon, Ghrairi said: "We are not from another planet. We come from a place that is just 45 minutes away from Doha. We are used to this heat."
Emirates have one significant advantage: Al Rayyan have nothing to play for, having already been consigned to finish bottom of Group D. However, Zob Ahan, already confirmed as champions of the group, have nothing to win against Shabab, the side two points ahead of Emirates in the group.
The RAK club qualified for the tournament last April when they were the surprise winners of the President's Cup despite eventual relegation from the Pro League.
They demonstrated their ability to compete in the group when they scored the opening goal away to Zob Ahan, and with home victories against Al Rayyan (2-0) and Shabab (2-1).
They have captured the imagination of their fans in RAK; more than 5,000 saw each of their three ACL home matches, including the 1-0 defeat to Zob Ahan last week.
"I have to thank our supporters, who have given us strong backing," Ghrairi said.
The other Emirates players suspended for the match are the first-choice defender Ali Mohammed Abdulrahman al Tenaiji, the midfielder Abdullah al Balooshi and the goalkeeper Ahmed al Zaabi.
However, Hadaf Said Ahmed, the defender who scored against Al Rayyan in March, returns from suspension, as does his centre-back partner Mustafa al Saedi.
Al Rayyan are coached by the Brazilian Paulo Autori and lie third in the Qatar Stars League. They lost 1-0 away to Shabab last week.
If Emirates finish second in the group they will play away to Al Sadd of Qatar or Al Nasr of Saudi in the last 16 on May 25.
Also tonight, Al Wahda conclude their involvement in Group C with a home match against Sepahan of Iran. Kick off at Al Nahyan Stadium is scheduled for 8.30pm.
The Abu Dhabi side, the defending Pro League champions, were eliminated from consideration for the last 16 when they lost 3-2 to the Uzbek side Bunyodkor in Tashkent last week.