Blackrock posted a serious warning to all-Leinster Schools Junior Cup contenders at Donnybrook yesterday as they scored eight tries in the elimination of St Gerard's.

The rout began within a minute. Full-back Jamie Waldron crossed for the first of his two tries and triggered a deluge of pressure.

Eoin Sullivan (2), the flying Cormac O'Connor and flanker John Fagan added tries before the break. Centre John Ronan kicked two conversions.

The St Gerard's out-half Eric Roche landed a first-half penalty and centre William Wong's penetrating run down the left wing set up full-back Ross Mooney for an admirable try two minutes into the new half.

Blackrock responded, however, with three more tries - from Ronan, which he converted himself before being replaced, Sullivan and Waldron, with Alan Henry adding two conversions.