Jires Kembo-Ekoko's goal gave Al Ain the lead at the break before second-half strikes from Alex Brosque, Omar Abdulrahman and Yousef Ahmed, the substitute, completed the rout last night at the Tahnoun bin Mohammed Stadium.
Helal Saeed exchanged passes with Abdulrahman before setting up Kembo-Ekoko, the unmarked Congolese forward, to make it 1-0.
And after the break, Al Ain ran away with it.
Brosque doubled the lead courtesy of an Abdulrahman pass. Then the UAE's Gulf Cup hero converted a penalty after a handball against Ahmed Ibrahim. Ahmed completed the scoring by tapping in a cross from Brosque.
Cosmin Olaroiu, the Al Ain coach, was happy with the three points but concerned with the upcoming schedule.
"The national team players will leave after this game and then we are cramped with matches in three different competitions - the league, President's Cup and the Asian Champions League," he said.
"We had a good result against Ajman but I am not satisfied with the performance. We have to still work on a lot of areas and as I have pointed out before, we cannot do it without the full squad."
Olaroiu said that, apart from Abdulrahman, the three other Gulf Cup players in his squad - Mohammed Ahmed, Mohanad Salem Al Enazi and Dawoud Sulaiman - were not ready to play the full 90 minutes since returning from national duty.