They had the game virtually sealed at half time after strikes from Omar Abdulrahman, Ismail Ahmed and Alex Brosque left them to enjoy a three-goal cushion.
Asamoah Gyan struck twice after the break to complete the rout tonight at the Tahnoun bin Mohammed Stadium.
Abdulrahman picked up a loose ball that failed to be cleared by the Wasl defence and neatly chipped it over Ahmed Mahmoud, the goalkeeper for the opening goal.
Ahmed rose above the Wasl defence to head a corner to double the lead past the half hour and Brosque was lethal with another header off Khaled Abdulrahman shortly before the break.
Gyan then added the second-half goals to complete the rout. The Ghanaian recently appointed as captain of the national team took his league tally to 12 from six games.
The first was from the penalty spot after Helal Saeed was brought down by Saoud Saeed, the Wasl defender, with the faintest of touches. He scored the next by beating the offside trap from a through pass off Helal Saeed and poke it past a hapless Mahmoud.
Al Ain had previously allowed Ahli to stage a second-half rally in a 6-3 defeat in their opener and last week surrendered a 2-0 lead to barely hold on to a 2-2 draw against Al Jazira.
But such was their dominance there was no such fears that they would lose the three points to Wasl. "We were better prepared both mentally and physically not to allow the lead slip away again as we did last week against Jazira," Omar Abdulrahman said during a post-match television interview.
"Having built a 3-0 lead at the break we got the pressure off our backs. Fortunately for us, the goals came thick and fast. At the end it was the three points that mattered."
Cosmin Olaroiu, the Al Ain coach, had the luxury of replacing Omar Abdulrahman after the hour to provide Ali Al Wehaibi, who was returning from injury, with valuable match practice.
It was Wasl's first defeat and Humaid Yousuf, the team manager, acknowledged they lost control of the game in the first half.
"After we went down 3-0 we knew it was very hard for us to get back in the game against a team like Al Ain," he said.
"All three goals in the first half were due to our own mistakes. We just can't do that and were punished. And it wasn't our day because nothing worked in favour of us. "Obviously it was very disappointing but we will regroup and get back in the next game."
Lucas Neill, the Australian who plays in central-defence for Wasl, said their performance was not nearly sharp enough. "Al Ain are champions; if you make a mistake against them, they punish you," he said.
The result is likely to prompt the Wasl management to speed their search for a replacement for Bruno Metsu, who stepped down last month because of illness.
Al Ain have now scored a remarkable 26 goals while conceding 10 in six league games.
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