Ghana superstar Asamoah Gyanâ€™s scored with a first-half tap-in that proved enough as Al Ain ended Al Ahliâ€™s treble dream with a 1-0 win in the Presidentâ€™s Cup final on Sunday.
Arabian Gulf League and Cup winners Ahli had won all three previous meeting this season, but it was the Boss who deservedly took the lead as the Ghanaian side-footed home in the 32nd minute.
Omar Abdulrahman had a great chance to make it two shortly after half-time but the Red Knights rallied in the second period and hit the woodwork twice in a matter of seconds, through Ahmed Khalil and Ismail Al Hammadi.
That would be the closest they came to an equaliser though as Al Ain saw out a nerve-shredding four minutes of injury time to seal their sixth Presidentâ€™s Cup title.
Coming against the team that has swept all before them this season while coached by their former boss, Cosmin Olaroiu, will only make the achievement sweeter for the Garden City club.
Whether it is enough to keep Zlatko Dalic in the Hazza bin Zayed Stadium hot-seat, only time will tell.
Ahli were bidding for a clean sweep of domestic honours, having also won the curtain-raising UAE Super Cup, but as kick-off approached in Abu Dhabi it was the supporters of Al Ain who were in better voice.
And after the national anthems and the Bossâ€™ now customary huddle, that fanfare from the stands transferred onto the pitch where Dalicâ€™s side controlled the game from the first whistle.
Omar Abdulrahman, the unexpected perpetrator of a first-minute reducer, flashed an effort wide from 25 yards in the 13th minute.
Sixty seconds later the playmaker found the ball in an inviting position again, thanks to a combination of Gyan and older brother Mohamed, but he dragged his shot past the far post.
Mohamed Abdulrahman would then force Ahli keeper Saif Yousif into a routine stop as the Red Knights were confined to using the pace of Ismail Al Hammadi on the break.
Although had Luis Jimenez not hurdled Mohammed Fayezâ€™s reckless challenge in the box in the 29th minute, the Red Knights may well have had a penalty.
Within three minutes, though, the Boss lead. Mohammed Ahmedâ€™s comical air shot mattered little as Al Ain maintained the pressure and when Basheer Saeed deflected Fayezâ€™s cross from the left into the path of Omar Abdulrahman, the No10 calmly played the ball across goal for Gyan to tap home.
It could have been worse for Ahli at the break but Yousif was able to tip an Ismail Ahmed header over the bar.
Al Ain keeper Khalid Essa looked far from happy with some of his team-mates as he left the pitch at half-time but within a minute of the restart his side almost doubled their lead.
Omar Abdulrahman found himself in acres of space but as he continued his run into the box Yousif was grateful to see his shot blocked behind.
And the Red Knights should have levelled shortly afterwards but having caught Al Ain napping in their right-back area, Ciel blazed over with Ismail Ahmed closing in.
But while Olaroiuâ€™s side were enjoying a greater share of possession, it was still their opponents who looked more likely to get another goal as Ibrahim Diaky went close twice within a minute.
Olaroiu reacted by throwing on Ahmed Khalil for the sub-par Hugo Viana, and the UAE striker would rattle the crossbar with a diving header, before Al Hammadi diverted the rebound onto the woodwork again.
Ahli now sensed their chance with Ciel whipping a free-kick just over the bar from 20 yards as the Boss looked to consolidate their advantage.
It looked a risky strategy against a side with four forwards and Jimenez now on the pitch but it was one that paid off as the Boss finished what had been a frustrating campaign on an extreme high.
Al AinÂ (4-2-3-1): Essa 7; M Ahmed 6, I Ahmed 7, Juma 7, M Fayez 6; Saeed 7, Radoi 7; Diaky 6, O Abdulrahman 7, M Abdulrahman 7; Gyan 8 Subs: F Fayez for M Fayez (73â€™, 6), Brosque for M Abdulrahman (78â€™), Barman for Diaky (84â€™)
Al AhliÂ (4-2-3-1): Yousif 6; Haikal 6, Abbas 7, Saeed 7, Sanqoor 6; Hassan 6, Viana 5; Al Hammadi 7, Jimenez 6, Ciel 5; Grafite 6 Subs: Khalil for Viana (64â€™, 7), Hussein for Haikal (82â€™)