United and Sharjah played out a 1-1 draw at Al Maktoum Stadium on Sunday in Matchweek 4 of the ADIB Cup.
Both goals came in the first half, with Dieu Mercy putting United ahead in the 39th minute before Clinton Nsiala struck an injury-time equaliser for Sharjah in the 45+5th minute.
The result takes United to four points in 10th place, while Sharjah move to five points in eighth.
The closing stages of the first half delivered plenty of drama. United broke the deadlock in the 39th minute when Dieu Mercy fired home with a powerful strike.
Sharjah had a golden opportunity to level just before the break, but Igor Coronado's 45+2nd-minute penalty was denied by an impressive save from United goalkeeper Stojan Lukovic.
The visitors continued to push forward and eventually found their breakthrough in the fifth minute of added time, with Clinton Nsiala reacting quickest to turn the rebound and make it 1-1.
Both sides pushed for a winner after the restart, but neither could find the decisive goal as the points were shared following an entertaining encounter.
Dieu Mercy became the first Canadian player to score in the ADIB Cup.