St Patrick's Athletic slipped off the top of the Airtricity League Premier Division table after a 1-1 draw with Dublin rivals Bohemians at Richmond Park.
Daryl Kavanagh gave the home side a 20th-minute lead but the visitors secured an unlikely point through Dinny Corcoran's goal 15 minutes from time.
The result, coupled with Dundalk's win over UCD, leaves the Saints a point behind the Louth club, albeit with a game in hand.
Bohs are now two points clear of the bottom two, Shelbourne and Bray.
Liam Buckley made four changes to the side that beat Bray 3-0 in the FAI Ford Cup last week with Aidan Price, Shane McFaul, Kavanagh and Christy Fagan, making his 50th appearance for the Saints, all starting.
John Russell remained out with an ankle injury while Greg Bolger started on the bench.
For the visitors, Karl Moore was back from suspension and Ryan McEvoy was better after an illness, as caretaker boss Owen Heary made two changes to the team that beat Shamrock Rovers two weeks ago.
Only two minutes had elapsed when Pat's forged their first chance, Aidan Price heading Killian Brennan's cross over when he should have made Bohs goalkeeper Dean Delany work.
And the home fans were looking for a penalty a few minutes later when Fagan twisted past Anto Murphy and appeared to be pulled back but referee Alan Kelly waved play on.
The home side were dominating proceedings, however, some slack play by McFaul saw Bohs win a free on the edge of the box but Ryan McEvoy blasted well wide.
Then St Pat's captain Conor Kenna had to be alert as Corcoran threatened when played in by a weak back-pass.
The Gypsies were soon back on the defensive with Kavanagh and Fagan causing problems without creating a clear chance.
But Saints made the breakthrough in the 20th minute.
Forrester, also making his 50th Saints appearance, picked up the ball on the edge of the area and split the Bohs defence to set Ger O'Brien free.
The right-back passed the ball across the six yard box and Kavanagh was on hand to side-foot home for his first goal since signing back from Cork City in July.
The Inchicore side pressed hard for a second and Delany had to save long-range efforts from Forrester and Byrne, twice.
The visitors, without the suspended ex-Saints captain Dave Mulcahy, struggled to keep possession, looked vulnerable at the back, and could consider themselves lucky to be just a solitary goal down at the break.
Heary introduced Keith Buckley and Stephen Traynor at the break and Bohs appeared reinvigorated, forcing two corners and managing to apply some decent pressure.
But the northsiders resurgence failed to yield a goal, McEvoy's shot from distance that was always comfortable for Brendan Clarke their best effort.
The league leaders began to creep back into the game and Fagan had the ball in the back of the net from Forrester's pass but the linesman raised his flag for offside.
With 15 minutes to play, Bohs, desperate for points in their relegation battle, had their lifeline.
Ian Bermingham left a backpass short and Corcoran rounded Clarke, who had rushed out to intercept.
The striker kept his cool and manoeuvred himself into a better position to slam the ball home to make it 1-1.
Buckley quickly introduced Anto Flood and Bolger, whose guile had been missed, particularly in the second half.
And the two combined with five minutes to play but Delany was equal to Flood's header and fellow sub Stephen Maher's follow-up was scrambled clear.
Price had two late chances for the Saints but headed and shot wide in injury time.