Institute substitute Paul McVeigh scored a dramatic 90th-minute winner to see off 10-man Warrenpoint and end a run of three consecutive defeats.
McVeigh turned and fired into the bottom corner from inside the area.
Institute dominated the first half of a match played in very wet and windy conditions but squandered a number of good scoring opportunities.
The hosts were up against it after having Darren King sent-off for a second bookable offence on 50 minutes.
The first chance of the game fell to Aaron Walsh, but his shot was comfortably gathered by Martin Marron.
Cormac Burke fired over the bar, Stephen Curry was off-target and Stephen O'Flynn's audacious 40-yard attempt went just wide of the post, with Marron off his line.
Dwayne McManus had a shot well saved by the feet of Marron, who also denied Declan McKeever.
Curry should have scored when through on goal, but he blazed wide, while Warrenpoint's best chance fell to Stephen McCabe, but his attempt was saved by Eugene Ferry.
Despite King's dismissal, Daniel Hughes could have found the net for Barry Gray's side but he lifted the ball over Ferry and over the bar when one-on-one with the 'Stute keeper.
The victory sees Paul Kee's outfit leapfrog north west rivals Coleraine into eighth spot in the championship standings ahead of Saturday's fixtures.
Warrenpoint are bottom, level on points with 11th-placed Dungannon Swifts.