Setanta Cup holders Drogheda have a battle on their hands to reach this year's knockout stages after Aidan O'Kane struck in the first half to hand Linfield a 1-0 win at United Park.
But the Blues had to survive a fierce onslaught from Paul Doolin's men in the second half before securing all three points.
Drogheda, already minus three strikers from their starting line-up through injury, suffered a further serious blow after only four minutes when Shane Barrett was stretchered off following a no-nonsense challenge by Chris Lindsay.
The home defence rode their luck on a number of occasions, but it was Doolin's side who almost struck when Paul Keegan's long-range free kick flew narrowly wide, and then Ollie Cahill went close after an enterprising run.
But Conor Downey saw his fierce drive blocked as Linfield attempted to turn the screw, and it was no surprise when the visitors struck on the half-hour, Aidan O'Kane sending a sweet volley past keeper Dan Connor from 10 yards.
Drogheda substitute Aidan O'Keeffe almost levelled within 60 seconds when he deflected a corner kick goal-wards, but Alan Manus in the Linfield goal was equal to the challenge, and O'Keeffe then fired inches wide after running onto Simon Webb's pass.
Yet Linfield could have extended their lead in first-half injury time when O'Kane shot over the bar after Peter Thompson’s initial cross had caused panic in the home defence.
Drogheda carved out their best attack of the game in the 56th minute when substitute Tony Grant sent Shane Robinson clear and his cross was volleyed over by Cahill.
Last season's eircom League Player-of-the-Year went even closer from longer range seven minutes later as Drogheda raised their game, and seconds after his introduction Declan O'Brien forced a superb fingertip save from Manus.
The Boynesiders also had a Graham Gartland header ruled out for offside, and Stuart Byrne twice saw goal-bound efforts deflected wide, before Robinson and O'Brien were each thwarted from close range.
Somehow the Irish League champions held on for a win that will make them firm favourite to advance to the semi-finals as Group A winners.
