Keith Fahey secured the three points for Pat's from a tempestuous Dublin derby that saw three red cards and plenty of controversy.
Fahey gave Pat's a dramatic lead on 14 minutes with a spectacular strike from at least 30 yards out that crashed through the Bohs defence and into the back of Brian Murphy's net.
Bohs fought back and Glen Crowe collected a pin-point accurate cross from Owen Heary on 21 minutes and unleashed a powerful left footed strike from the edge of the box that Pat's keeper Barry Ryan excellently turned around his post with his right hand.
The Pat's defensive wall then blocked down a Mark Rossiter free kick on 24 with his rebound shot flying high and wide into the shopping centre end terrace.
Crowe headed down neatly for Kevin Hunt inside the area on 35 but Damien Lynch managed to get a toe to the ball and clear the danger while Crowe himself shot just wide on 41.
Bohs started the second half in ferocious fashion and chased an equaliser. The looked for a penalty early in the second period a when JP Kelly cross appeared to be met by a Pat's hand as it arrived in the goalmouth. However, the claims were waived away by ref Dave McKeown.
Pat's were reduced to 10 men on 80 minutes when former Bohs man Dessie Byrne was given a second yellow. That became nine on 85 when goalkeeper Ryan and Bohs' Killian Brennan were red carded following an altercation which saw all 22 players get involved and make their opinions known.