The 50-year-old - who was dismissed as Argentine national coach after last year's World Cup - had guided the side to two wins after an opening run of three defeats, albeit two friendlies and a Cup match, but Dubai brought him back down to earth.
"I want to apologise to the Al-Wasl supporters for this defeat," said Maradona, who last month advised fans to stay at home and watch a DVD if they found it too stressful to watch the team.
"I am very sad. We were on the right path with two successive victories and now we must focus on the championship and not look back.
"I hope that this defeat will not affect the morale of the squad who must learn lessons from this defeat."