Ronan Coughlan scored for the second week running with the only goal of the game at Dalymount Park as St Patrick's Athletic beat Bohemians for the first time in 10 games stretching back over three years.
Unbeaten in their opening three matches, the result moves Stephen O'Donnell's Inchicore side joint top of the Premier Division table in a three-way split with Finn Harps and Sligo Rovers. Bohemians, last season's runners-up, still await their first victory.
With a switch to a 3-5-2 formation, St Patrick's shaded the first half with Robbie Benson shooting narrowly wide with the only real opening following a mistake by defender Rob Cornwall.
The sides swapped half chances early in the second half before the arrival of the goal the game so desperately cried out for on 62 minutes. Unsurprisingly, it stemmed from a set-piece. It was all about the pace and flight on Benson's corner to the back post, which was met by Coughlan whose meaty header goalkeeper James Talbot could only help into the roof of his net.
Finn Harps also remain unbeaten as they maintained their encouraging start to the season with a 1-1 draw at newly promoted Drogheda United to enjoy another week at the summit.
Karl O'Sullivan put Ollie Horgan's side ahead on 56 minutes with he drilled a powerful shot low to the net from the edge of the area. Drogheda were level six minutes later with a real team goal as Darragh Markey, Ronan Murray and James Brown were all involved to set up Mark Doyle for a tap in.
Despite finishing with 10 men, Kevin Sheedy's Waterford earned their first win of the season as they came away from the Brandywell with a 2-1 win to leave Derry City rooted to the foot of the table with no points from two games.
It proved a bitter sweet night for Waterford captain Oscar Brennan, he scored what proved the winning goal before being sent off for a second booking.
Shane Griffin put Waterford in front on the half hour mark with a well-struck free kick before Derry levelled in the final action of the half when Cameron McJannet shot home after Eoin Toal headed on a Will Patching free kick.
Brennan restored Waterford's lead six minutes into the second half when following up to shoot home the rebound after Nathan Gartside had parried his penalty kick. An 81st minute foul on Patching then brought a second yellow card in quick succession for Brennan who was dismissed.