Shamrock Rovers 1-0 Derry City
Derry City's title ambitions are all but over after they lost to champions Shamrock Rovers at Tallaght Stadium.
Daniel Lafferty twice went close in the first half while Eamonn Zayed's header cannonned off the inside of the post.
Rovers scored in the 50th minute when Rohan Ricketts lobbed the ball over Ger Doherty's header after a mix-up between the keeper and Stewart Greacen.
The home side continued to dominate and Gary Twigg had an effort blocked, while Doherty saved from Ronan Finn.
Lafferty had the first clear chance of the game but his left-foot free-kick from outside the penalty area went wide of the post.
Lafferty then got on the end of a corner but stabbed the ball wide of the upright.
Zayed then rose highest but his header came off the woodwork.
Rovers had claims for a handball by Barry Molloy inside the area turned down before the break.
After half-time the misunderstanding between Doherty and Greacen allowed Ricketts to score with the side of his foot for his second of the season.
Rovers could have extended their lead but settled for the 1-0 victory which leaves them on the brink of a second successive league title.
Rovers have 71 points, Sligo Rovers 67 and Derry City 63, with the Candystripes having a match in hand over their two title rivals.
Stephen Kenny's side play Galway United at home on Sunday.