Goals from Abdullah Al Astaa and Waleed Al Gizani in the second half earned the Riyadh-based club their second win of the campaign over the United Arab Emirates giants and moved the Saudi side onto 10 points.

That leaves them level with Sepahan, who they meet in Esfahan in two weeks' time, with the Iranian side holding a slender advantage having defeated Al Shabab in their previous meeting in Riyadh in March.

As a result, a draw will be enough for Sepahan to go through. Al Ain, meanwhile, are eliminated from the competition, the first time the 2003 winners have failed to progress to the knockout stage.

Al Shabab always looked the more likely to pick up the three points and could have opened the scoring in the 28th minute when Naji Majrashi's effort went into the side netting of Waleed Salem's goal.

One minute later, Al Shabab midfielder Nashat Akram tried his luck but his powerful shot from the edge of the area went straight at Salem.

Al Ain's sole effort in the first half came five minutes before the interval when Sultan Al Kalbani sent a cross from the left flank into the area only for Gharib Harib to send his effort wide.

Ten minutes after the break, Hassan Maaz's shot was denied by the woodwork but three minutes later Al Astaa struck, the 20-year-old defender scoring after he had been sent through by Abdoh Autef.

Akram almost doubled Al Shabab's advantage 17 minutes from time when Salem was called into action before Naji Majrashi sent his effort over the bar.

Cameroonian striker Frank Ongfiang saw his hopes of claiming an equaliser for Al Ain dashed by goalkeeper Mohammad Khojah, who recovered in time to punch Rami Yaslam's follow-up wide for a corner.

However, with two minutes to go, Al Shabab put an end to Al Ain's hopes of a fifth successive appearance in the quarter-finals when Al Gizani beat Salem and Mussallem Al Hamadani to score into an empty net.