Shamrock Rovers failed to take advantage of dropped points by teams around them in a 1-1 draw against Drogheda United.
After Shelbourne's 2-1 defeat to Sligo Rovers on Saturday and Derry City's draw against Dundalk on Friday night, the champions had the opportunity to put themselves back in the title race.
A goal from Darragh Burns put them ahead after six minutes gave them the lead, but Drogheda equalised in the 74th minute through Douglas James-Taylor to leave Shamrock Rovers in fifth, 10 points behind leader Shelbourne.
The result also leaves Drogheda bottom, two points behind Dundalk.
Jason McCelland gave Stephen Kenny's side the lead in the 37th minute, before Edward McCarthy brough Galway level in the 53rd minute.
In Sunday's other game, St Patrick's Athletic held Galway United to a 1-1 draw.
The result put a dent in Galway's hopes for European football, while St Pat's are eight points ahead of Dundalk, who occupy the relegation play-off zone.
