Brendan Clarke saved Tadgh Purcell's second-half penalty at St Patrick's Athletic and Cork City played out an entertaining 0-0 draw in Richmond Park.
Clarke got down low to save Purcell's weak effort, with the Cork striker also seeing a long-range shot strike the bar earlier in the half.
Pat's had plenty of openings with Chris Forrester as the heart of most of their good play but they could not make a breakthrough.
Pat Flynn, Darren Meenan and Jake Kelly came in for Greg Bolger, Mark Rossiter and Sean O'Connor as Pat's reshuffled due to injuries.
Cork left Dan Murray on the substitutes bench with John Dunleavy handed a starting role.
Cork had more of the ball in the opening minutes although it was Pat's that first threatened first as Pat Flynn's excellent diagonal ball picked out Darren Meenan. The former UCD player cut back to fire into the side-netting.
Cork goalkeeper Mark McNulty was booked in the ninth minute as he left his box and connected with Jake Kelly close to the touchline. Kelly wasted the resulting free-kick.
The visitors wasted a good opening shortly afterwards as Tadgh Purcell's pass left Vinnie Sullivan and Daryl Horgan facing just two Saints defenders. However Sullivan's tame effort trickled into the hands of Brendan Clarke, much to the frustration of Horgan who had worked space on the corner of the box.
As Purcell and Sullivan were allowed to muster chances without greatly troubling Clarke, Chris Forrester created his own opportunity, a common trait as the half went on. Hs produced brilliant trickery to see off Gearoid Morrissey and shoot from 25 yards, forcing McNulty into a save at the second attempt.
Purcell then fluffed an excellent chance to give Cork the lead in the 22nd minute as Horgan's pass teed up his team-mate with just Clarke to be again. But again the shot lacked conviction and Clarke gathered with ease.
Forrester's next shot at goal was a curling free-kick that McNulty saw wide of the post just short of the half-hour mark as an entertaining game remained scoreless.
Cork stood off the 19-year-one again when he was allowed time to lash another fine effort towards goal that the Rebels 'keeper had to push away with the ball destined for the top corner
The closing minutes of the half produced more open play without a breakthrough.
Pat's started the second-half strongly and attacked from the off. Forrester once again was the free man as his back-post header struck Purcell and McNulty claimed the ball.
Cork had another excellent chance on the hour as Horgan drove down the right and passed to Sullivan, following Purcell's dummy, but the shot was wayward once more.
The Rebels were doing well to compete with a side second in the table but they lacked a cutting edge in the final third to produce that opening goal.
Tadgh Purcell went agonisingly close to ending the Rebels' frustration as he took the ball from Davin O'Neill and sent a dipping shot onto the crossbar from 25 yards.
Forrester should have claimed the goal his play deserved when substitute Sean O'Connor slid in his team-mate following John Dunleavy's slip but the shot was blocked by McNulty.
The game built to an exciting conclusion as first Ian Bermingham struck the angle of the woodwork and then Cork won a penalty after Kenny Browne's poor challenge on Purcell.
Purcell stepped up for the spot-kick but Clarke prevailed, and the Rebels had to hang on following late pressure from the home side.
The Saints trail Sligo Rovers by three points ahead of the Bit o' Red's meeting with Shamrock Rovers tomorrow.