Last year's champion Shahjalal and runner-up Jibon Boli did not participate in this year's competition
Diego Costa gave Europa League holders Atletico a dream start against Champions League winners Real by firing them ahead after 49 seconds, knocking down a long pass and smashing the ball into the net from a tight angle.
Real, who beat Atletico in the 2014 and 2016 Champions League finals and knocked them out of the competition in 2015 and 2017, levelled when Karim Benzema leapt at the far post to nod in a cross from Gareth Bale in the 27th minute.
Saul punished Raphael Varane's mistake by scoring with a stunning volley to put Atletico ahead again in the 98th minute and fellow academy graduate Koke sealed the victory six minutes later.