Icasa surprisingly held Vasco da Gama to a 1-1 draw in the first leg of their Copa do Brasil last 16 tie at the Sao Januario Stadium.
After just eight minutes Vasco were handed the lead as Icasa goalkeeper Ari sliced an attempted clearance off the post and agonisingly over the line.
Vasco failed to take advantage and after a strong period of pressure in the second-half and Marciano connected with Leozinho's cross with 15 minutes remaining to snatch a crucial away goal for Icasa ahead of Thursday's second leg in Ceara.
"This result is like a defeat for us. We did everything badly," said Vasco defender Tiago.
Elsewhere, Fluminense earned a valuable 2-2 draw at Goias.
Fluminense opened the scoring after just two minutes through Luiz Alberto but Rafael Toloi connected with Ze Carlos' corner to pull Goias level.
A header from former Lyon midfielder Fred regained the lead for Fluminense in the last minute of the first half but in the second-half Felipe Menezes pulled Goias again back on level terms ahead of the next week's second leg at the Maracana Stadium.