Shamrock Rovers did the treble over Derry City in dreadful conditions at Tolka Park last night to keep their European hopes alive as they leapfrog Cork City into third place in the Premier Division table.

Superbly executed goals from Richie Purdy, Tony Cousins, his 14th of the season, and Marc Kenny battered the champions into submission and back into further trouble in the table.

Ironically, Derry began the game as if they had something to prove and should have been 3-0 up inside the opening 11 minutes.

Rovers gradually steadied themselves and took the lead four minutes before the break. Tracey sent Purdy through on goal with a precise pass and Purdy did the rest.

Rovers continued to control the game in the second-half and Cousins got their second after 60 minutes. Brian Morrisroe crossed at the second attempt and Cousins turned cleverly in the box to crack home a low shot from 12 yards.

Having beaten them twice already, Rovers were toying with the champions now and Cousins laid the ball off for Kenny to add the third with a low, curling drive from the edge of the box on 77 minutes.

Derry got their consolation from an 88th minute penalty converted by Paul Curran after Brazil had pulled down Coyle.

Shamrock Rovers: Horgan; Britton, Whelan, Brazil, Dunne; Tracey, Colwell, Purdy, Kenny, Morrisroe; Cousins. Sub: O'Neill for Kenny (86 mins).

Derry City: O'Dowd; Doherty, Curran, Dykes, Hargan; Taggart, Bell, Hegarty, Keddy; Beckett, L Coyle.

Referee: R O'Hanlon (Waterford).