Bohemians go top of the table after a third successive win, taking advantage of Shamrock Rovers' ill-discipline in Phibsboro.
Reduced to ten men in the first half, Rovers were thereafter up against it and coughed up a silly penalty that decided a pretty scrappy game, Dinny Corcoran scoring for the third night running.
Bohs will be delighted with this triumph over their hated rivals and the third successive clean sheet – with James Talbot having next to nothing to do here in nets – shows what a remarkable job boss Keith Long has done, despite the limited budget and the exodus of three centre backs in the off-season.
Rovers were the better side with 11 men but will be sickened to again surrender to the Gypsies, whose last six games against the Hoops in the league have yielded an incredible 16 points.
Hoops boss Stephen Bradley shuffled his line-up after the victory over Derry on Friday, going 3-5-2; in came Joey O'Brien, Greg Bolger and Trevor Clarke, with Ronan Finn, Dan Carr and Roberto Lopes on the bench.
Jack Byrne was really lively for the visitors and he was involved on at least two occasions in a counter-attack that concluded with his effort on goal being blocked by the promising James Finnerty.
At the other end, Bohs belatedly threatening, Corcoran ran out of room in the box whilst looking to get a shot away.
Darragh Leahy had a fine chance at the back post on 25 minutes but headed straight at Alan Mannus at the end of Keith Ward's corner-kick.
The narrative changed on 29 minutes when Aaron Greene was given a straight red for a challenge on Ward. In real time it looked nailed on, though replays suggest it wasn't such a clear-cut decision.
Byrne, the best player on the park, was then taken down by Conor Levingston, who was rightly yellow-carded. It was all getting spicy on a beautiful February night.
Greene's rash tackle will have had Bradley fuming, while his mood was no better too for Greg Bolger's carelessness on the ball in the first half. The midfielder's form would at least improve somewhat in the second period.
Corcoran remained a threat, curling another attempt over the bar with time running out in the first half.
Byrne was hauled off at the interval as Bradley introduced Carr, a move that hardly impressed the temperamental attacker, considering his excellence in the first half.
Ward is a delightful player on his day and his exquisite cross five minutes after the break found Luke Wade-Slater but he headed wide with Mannus looking relieved in front of the visiting fans.
Despite being a man down, Rovers looked threatening, and Watts' cross was almost turned in by O'Brien.
The lead goal came on 68 minutes. Ward ran at Ronan Finn and after an absolutely needless challenge by the latter, Corcoran guided the spot-kick into the corner.
Rovers nearly equalised when the outstanding Lee Grace headed goalward and Keith Buckley's defensive header had to be batted away by a hitherto unneeded Talbot.
Ward – later given a standing ovation when taken off and replaced by the returning Ali Reghba – nearly doubled Bohs' lead after a lovely pass from Conor Levingston but his initial shot was blocked by O'Brien and his second one went over.
Keeper Mannus caused consternation in the home box from two corner-kicks in injury time but the fairytale ending would not happen as Bohs held out quite comfortably.
Bohemians: Talbot, Pender, Cornwall, Finnerty (Barry 77), Leahy (Kirk 65), Ward (Reghba 81), Wade-Slater, Levingston, Buckley, Mandriou, Corcoran.
Shamrock Rovers: Mannus, Boyle (Lopes 37), Grace, O'Brien, Kavanagh, Byrne (Carr 46), McEneff, Watts (Finn 60), Bolger, Clarke, Greene.
Referee: Rob Harvey (Dublin).