The current leaders had won just two of their previous five league fixtures prior to Sunday's fixture and looked destined for another setback when Mirko Vucinic scored an 87th-minute opener for Al Jazira, who would have gone top with a win.
However, the lead lasted just two minutes as Fadhel capitalised on a goalkeeping error from Ali Khaseif to preserve Al Wahda's one-point advantage over their opponents at the summit.
Third-placed Al Shabab also left it late to snatch a point in their 2-2 draw at Al Wasl.
Goals from Abdalla Mohammed and Fabio Lima gave the home side a comfortable lead at the break, while both teams were reduced to 10 men as Mohammed Ali Ayed and Caio were both handed first-half red cards.
Essa Obaid tapped in to reduce the deficit just before the hour mark and Al Shabab were served a boost when Waheed Ismail was shown a second yellow card, leaving Al Wasl with nine men.
However, it was not until the sixth minute of stoppage time that Edgar headed a dramatic equaliser to earn a hard-fought point.
It proved to be a difficult day for teams in the top half of the division, Bani Yas the only team to post a victory this weekend - 7-0 winners at Al Fujairah.
That success saw them leapfrog three other teams into fourth, with Al Nasr and Al Ain playing out a 1-1 draw, and 10-man Al Ahli losing 1-0 at home to Emirates.
Al Sharjah boosted their survival hopes on Saturday with a 4-0 win at Ajman, but remain just three points clear of the drop zone.
In the weekend's remaining fixture, Al Dhafra registered a comfortable 3-1 triumph over beleaguered Al Ittihad Kalba, despite having a man sent off late on.
