Emelec suffered just their second loss of the Ecuador Serie A season, beaten 2-0 by Barcelona on Saturday.
Ariel Nahuelpan struck a brace at Estadio Monumental Isidro Romero Carbo as Barcelona stayed sixth with the win.
Emelec, who are three points clear at the top despite the loss, have two games in hand over their nearest rivals.
Nahuelpan headed in the opener from a set piece four minutes into the second half to put Barcelona ahead.
The Argentine striker used his height and strength for his second goal three minutes later, heading in at the back post after a neat team move.
Deportivo Quito were unable to capitalise on Emelec's slip-up, held to a 0-0 draw at home to bottom side Macara.
LDU Quito remain third after drawing 1-1 at Manta, while Universidad Catolica were beaten 1-0 by Independiente.
Andres Rios scored a brace to lead seventh-placed Deportivo Cuenca to a 3-1 victory at LDU Loja, who stay in 11th.
El Nacional and Deportivo Quevedo played out a 1-1 draw.