Drogheda United had more to gain from this Premier Division goalless draw at Turner's Cross than the home side.
Cork City preserved their unbeaten home record but Paul Doolin's side maintained their eight point advantage over the Leesiders at the final whistle.
Cork were hit by injury woes before kick-off when Liam Kearney was ruled out with a calf strain and then top scorer Roy O'Donovan was forced out in the warm-up when he did his hamstring.
Cork had Joe Gamble back from suspension and Cillian Lordan stepped into the breach.
Drogheda made three changes from their mid-week 1-1 draw with Libertas in San Marino as Simon Webb, James Keddy and Paul Keegan all started for Gray, Whelan and Sami Ristila.
It was a tense, close fought first half of few chances.
Mick Devine saved bravely at Aidan O'Keeffe's feet on 10 minutes and then Leon McSweeney was just wide at the other end after Colin Healy and John O'Flynn had prised an opening.
Sean Kelly headed over from Farrelly's 40th minute corner and Dan Connor saved brilliantly from Dan Murray's header as the half ended goalless.
The second half was similar to the first with goal chances at a premium again though Cork were guilty of a bad miss on the hour.
Healy and McSweeney set up Denis Behan but he shot wide when it looked easier to score.
