Cameroonian Song recently joined Djibouti outfit Arta Solar 7.
There has been speculation that the Gabon attacker wanted away from the Gunners so that he can play Champions League football
The 48-year-old Spaniard was fired following the 2-1 home defeat to Eintracht Frankfurt in Thursday's Europa League match.
Atletico's triumph comes after agonising defeats to Real Madrid in the Champions League finals of 2014 and 2016
After a 1-1 draw a week ago in London, Diego Costa grabbed the decisive goal just before half-time in Spain as Atletico reached a fifth European final...
The six players who could decide the game
Despite dominating last week's first leg against Anderlecht, United returned from Brussels with a 1-1 draw.
Sign up to receive our free newsletter