A brilliantly contrived and sublimely executed goal from top scorer Tony Cousins lifted Shamrock Rovers to the top of the Premier Division table and inflicted a potentially mortal blow to Derry City's hopes of retaining their title at Tolka Park last night.

Rovers exorcised the ghost of their dismal display in Kilkenny last week with a lightning start which yielded the game's only goal after 12 minutes.

Cousins, leading a lone but very effective effort up front, frightened Derry as early as the fifth minute when he skipped past both Gavin Dykes and Paul Curran only to be thwarted by a good save from Tony O'Dowd.

But O'Dowd could only make a despairing dive seven minutes later as Cousins rewarded Rovers' power-play start with an excellent goal.

Marc Kenny and Brian Morrisroe worked the ball up the left, Derek Tracey helped on the cross, and Cousins teed the ball up with his right toe before volleying home with his left foot from just inside the box.

Derry came into the game steadily and soon began to run midfield with Paul Hegarty head and shoulders above anyone on the pitch. But despite their grip on the game, Derry struggled to break down a resolute Rovers defence.

Peter Hutton shot well wide on 22 minutes before Rovers survived Derry's only real chance of the match four minutes later.

Gary Beckett peeled off marker Richie Purdy to latch on to Eamonn Doherty's free-kick, but Rovers goalkeeper Robbie Forde did superbly to deflect away Beckett's low shot with his feet.

Derry completely ran the game in the second half, with Rovers scarcely getting out of their half. But some dreadful crossing from the flanks and a uncanny lack of penetration up front cost Derry the game.

Hegarty shot narrowly over twice within four minutes of the restart, while the closest Derry came to scoring thereafter was when Liam Coyle released Peter Hutton through the middle, but the Derry skipper hurried his shot.

Shamrock Rovers: Forde; Britton, Whelan, Purdy, Dunne; Tracey, Colwell, O'Neill, Kenny, Morrisroe; Cousins. Subs: Brazil for O'Neill (67 min).

Derry City: O'Dowd; Doherty, Dykes, Curran, Brunton; Mohan, Hegarty, Hutton, Hargan; L Coyle, Beckett.

Referee: H Byrne (Dublin).