The UAE champions face a tough challenge to reach the Champions League group stage, needing to eliminate Ronaldo, Sadio Mane, and their Nassr team at Mrsool Park in Riyadh.
However, recent form will give Shabab Al Ahli some cause for optimism. The Dubai club opened their Adnoc Pro League title defence with a 3-0 win away at Ajman, despite playing more than 70 minutes with 10 men.
Contrastingly, Nassr have lost both of their Saudi Pro League games so far, following up a 2-1 defeat at Steven Gerrard's Al Ettifaq, which Ronaldo missed as an injury precaution, before a shock 2-0 home defeat to Al Taawoun with the Portuguese superstar back in the team.
Nassr did, however, start the season by winning the King Salman Club Cup trophy, defeating Al Hilal in the final.
Abbas is aware of the challenge awaiting Shabab Al Ahli but insisted the team will do all they can to secure victory and passage into the group stage.
"We will give all our efforts to make our fans happy," the 38-year-old captain said. "Our preparations went well, and we are ready for this important match."
The Shabab Al Ahli squad arrived in Riyadh on Monday and took part in a training session on the Mrsool Park pitch in the evening, and manager Marco Nikolic has backed his players to shine against Nassr.
"We will give our best against a strong opponent and we will strive to reach the next stage," he said. "We need to focus. We respect Al Nassr as a big team with good and experienced players [but] we also have quality players."
Only one UAE club have secured their place in the Champions League group stage - 2022 league champions Al Ain - but Sharjah are also aiming to join them when the back-to-back President's Cup winners take on Iranian side Tractor in Tabriz on Tuesday.