Emelec conceded two second-half goals as they were beaten 2-0 at home to Olmedo on Sunday, while Independiente del Valle routed LDU Loja 4-0 the day before.
Gustavo Quinteros' Emelec remain top of the table on 34 points, but their lead has been cut to six following Independiente del Valle's (28 points) comprehensive triumph.
Emelec and Olmedo renewed acquaintances having played out a 1-1 draw in their catch-up game midweek.
But it was Olmedo who emerged winners thanks to goals from Cristian Palacios and Byron Cano at the Estadio George Capwell.
Olmedo hit the front five minutes after the break through Palacios, who fired the ball into an empty net.
The visitors' doubled their lead 10 minutes later when Cano sprung the offside trap following a turnover in the middle of the pitch.
Independiente del Valle are hot on their trail after Fernando Guerrero, Daniel Angulo, Arturo Mina and Jonathan Gonzalez were all on target in the crashing win at the Estadio General Ruminahui del Valle de Los Chillos on Saturday.
In other results, Universidad Catolica leapfrogged LDU Loja into third position following their 2-1 win at home to Manta.
Cristian Lara bagged a double as seventh-placed Deportivo Quito won 2-0 against El Nacional, who suffered back-to-back defeats.
Cellar-dwellers Deportivo Cuenca earned a point at home to fellow strugglers LDU Quito in a 0-0 draw.
Meanwhile, second-bottom Mushuc Runa also played out a goalless draw with Barcelona.
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