Dave Donnelly reports from Richmond Park
Ali Reghba struck twice in two second-half minutes as Bohemians under-19s added the Enda McGuill Cup to their growing trophy cabinet.
Neill Byrne's headed goal inside the first two minutes had set the Saints on their way and Darius Kierans' men were by far the better side for the first 55 minutes.
The home side seemed to tire as the second half wore on, however, and they were stung by two quickfire goals from former Shelbourne striker Reghba.
Having dominated for most of the match, the Athletic were unable to summon back the adventure and drive with which they'd started and had Brian Maher to thank for keeping the score down.
Craig Sexton's Bohemians side discovered the identity of their UEFA Youth League earlier this afternoon with confirmation they'll face FC Midtjylland of Denmark over two legs.
They got off to the worst possible start in Inchicore, however, as the Saints took the lead wih the very first attack of the game.
Jason Grouse swung in a corner from the right-hand side and it was met by the head of the winger Byrne. Goalkeeper Sean Bohan got his body behind it but couldn't keep the ball out of the net.
Bohs had a chance of their own to level from a corner but Peter Adigun's delivery was headed wide by Lee Rock, but they were to see little of the Saints area for the rest of the half.
The visitors were being caused all sorts of problems by Pats' shape with two high-pressing midfielders, and the physically-imposing Richie O'Farrell was particularly prominent.
He won the ball high up the pitch to tee up Neill Byrne for a cross that was cleared by Mitchell Byrne, and he Jake Walker did likewise to set up O'Farrell to curl a shot just over.
More good link-up play between O'Farrell and Neill Byrne saw the former cross from the left for captain Luke Heeney, whose shot rebounded off the post and wide – a let-off for the Gypsies.
The Athletic's attacking shape was leaving lots of space in behind, however, and Reghba might have done better when played in by the impressive Ryan Graydon, but he couldn't keep his shot down.
Pats did have the ball in the net once more as Walker arrowed a header past Bohan from a terrific Paul Cleary cross, but it was ruled out for what must have been the tightest of offside calls.
The second half began much as the first finished but gradually Bohs gained a foothold, and it took a well-timed interception from Luke McNally to deny Graydon a goal from Reghba's cutback.
The Saints, whose relentless pressing up the field had caused Bohs such problems in the first half, began to retreat and they paid the price just past the hour mark.
Andy Lyons' free kick from the right found Ali Reghba with a free header, and he sent the ball looping over the helpless Maher.
Barely a minute later, Bohs caught Pats rapid on a counter-attack and Danny Grant pulled the ball inside for Graydon, whose first-time pass slipped in Reghba and he slotted the ball under Maher.
Maher was on top form to deny Adigun what would surely have been the clincher when he was played through by Reghba, the keeper standing tall to deflect the ball away from goal.
The Athletic's best chance came eight minutes from time as Cleary hared down the right and pulled back for Walker, but he couldn't rap his foot around the ball and Bohs survived.
And it was Bohs who were pushing for a third goal in the dying moments, and Maher pulled off an outrageous stop to deny substitute Marlon Matrisha from inside the six-yard box.
St Patrick's Athletic: Brian Maher; Paul Cleary, Joe Manley, Luke McNally, Ryan O'Shea; Aaron Townley (Mark Kelly 86), Richie O'Farrell, Luke Heeney (Mikey O'Keane 75); Jason Grouse (Cian Hughes 63), Neill Byrne, Jake Walker.
Subs not used: Adam Leonard (gk), Brian McGivern, Padraig Finnerty, Conor Cowley.
Booked: Aaron Townley (79).
Bohemians: Sean Bohan; Andy Lyons, Mitchell Byrne, Lee Rock, Peter Adigun (Callum Keane 93); Dylan Thornton (Jamie Hamilton 58), Alex Kelly, Ryan Graydon (Steven Nolan 74); Danny Grant (Marlon Marishta 86), Promise Omochere, Ali Reghba.
Subs not used: Alex Nevin (gk), Seamus Curley, Jordan Carroll.
Attendance: 400 (estimate).
Extratime.ie Player of the Match: Ali Reghba (Bohemians).