Papa Waigo broke the deadlock in the ninth minute and doubled his tally in the 42nd - four minutes after Marcelo Silva had put the visitors further ahead.
Issa Ahmed Santo (75), Adel Abdullah Basuleiman (80) and Srdjan Andric (90) rubbed further salt into the wounds as Al Wahda marched to the top of the fledgling table.
Bani Yas are level on points with the league leaders after coming from behind for a 3-2 triumph at Dubai SC.
Alhassane Keita had put the hosts in front and although Andre Senghor levelled on the stroke of half-time, Richard Porta put Dubai ahead for the second time in the 75th minute.
Nawaf Mubarak hit back three minutes later before Mohammed Jaber sealed all three points for Bani Yas with his last-gasp strike.
Libano Batista Grafite also left it late as Al-Ahly Dubai escaped from Al-Wasl with a 2-2 draw.
Mariano Donda's first-half strike was cancelled out by Grafite eight minutes after the interval and while Emiliano Alfaro re-established Al-Wasl's advantage, Grafite struck in the final minute to ensure a share of the spoils.