It appeared as though the deadlock had been broken in the 54th minute of a cagey contest.
Aliou Badji bundled the ball into the back of the net after seeing a corner flicked goalwards.
He wheeled away in celebration, but his joy was cut short as the on-field officials called on technology to make a final ruling.
The VAR deemed that Badji had kicked the ball out of the hands of Ecuador goalkeeper Jose Cevallos, resulting in the effort being chalked off.
Senegal’s bad luck continued as they saw Cavin Diagne sent off for a second bookable offence, but a goalless stalemate was enough to see them through to the second round.