Gary Twigg sent Shamrock Rovers back to the top of the Premier Division with the only goal of this Dublin derby with St Patrick's Athletic.
Twigg struck seven minutes after the break as he finished off a five-man move from the edge of the area.
St Pat's played their part in a energetic encounter, but the closest they came was Daryl Kavanagh's first-half shot that struck the outside of the post.
Rovers boss Michael O'Neill was dismissed midway through the second half, but his side held on for victory.
The visitors' performance showed some tiredness from their endeavours in the Europa League during the week, but they remain serious title contenders even though their long unbeaten run is over.
O'Neill sprang a surprise by leaving Gary O'Neill on the bench and starting with Ciaran Kilduff alongside Twigg in attack.
After Thursday's game in Iceland, St Pat's made just one change as Anto Murphy came in to replace Paul Crowley in midfield.
It was a lively opening with plenty of committed challenges, with referee Dave McKeon issuing two bookings to each side inside the first 15 minutes.
Despite the physicality on show, there was no shortage of good football with chances created at both ends.
Ronan Finn had the first opportunity as skipped past Bermingham and surged into the box. But he decided to go for goal, rather than pick out Twigg or Kilduff, and the shot flew wide.
At the other end, Kavanagh out-paced Stephen Rice and pulled the ball back across the box, but Derek Doyle could only fire straight at Alan Mannus.
The home side had the slight upper hand midway through half, but Twigg and Gary McCabe sent efforts just wide of Rogers' goal. St Pat's were grateful to Rogers for keeping it scoreless as he used his feet to keep out Enda Stevens' low drive.
Kavanagh's pace had been a threat to the Rovers defence but it was his low shot that caused concern as it bobbled through and hit the outside of the post. Minutes later, Derek Doyle's header from Stephen Bradley's free-kick looped over.
Rovers finished the half the stronger with Dennehy's drilled free-kick whizzing wide and Rogers keeping out Twigg's header.
The home side took the lead in impressive fashion as a sweeping move involving Finn, Stevens, Rice and McCabe was finished off by Twigg slotting his shot past Rogers.
Surprisingly after the four early bookings, it was Michael O'Neill who was the first man to be sent-off, as he was dismissed for taking his frustration out on a water bottle.
The recent busy fixture list seemed to have caught up with Pat's after the break and Shane McFaul, David McMillan and Ian Daly were brought on as fresh legs.
O'Neill, who was trying to orchestrate things from this new position in the press box, brought Dean Kelly on for Kilduff. It was Kelly who nearly doubled the lead when he volleyed Dennehy's cross outside the upright.
The substitutions gave St Pat's the boost they needed and they could have been level if Kavanagh and Daly had not got in each other's way in the box.
St Pat's left gaps at the back as they pushed forward in a desperate attempt to equalise and Rogers was needed again to keep out Finn's drive.
The closest the visitors came to snatching a late point was McFaul's glancing header from Doyle's corner that flew over the bar.
The home fans went bouncing home singing 'we are top of the league', while Pete Mahon will have a job lifting his players for the second leg against IBV on Thursday after two defeats in four days.
© RTÉ Sport