Medhi Benatia's Al Duhail defeated Al Sadd 4-1 to lift the Emir Cup at the newly-opened Wakrah Stadium on Thursday.
The Red Knights fought back from a goal deficit as Edmilson's brace and goals from Yusef El Arabi and Ali Afif gave them the coveted title at the expense of the league champions.
Algeria's Baghdad Bounedjah was on parade for Al Sadd but was sent off late in the game for an off-the-ball incident through VAR.
The triumph secured Benatia's first title in the Middle East since he moved from Serie A club Juventus in January.