The two teams in All-County Football League Division 1 action on a beautiful, breeze-free Friday evening in Rathangan knew that only the victor would remain in contention for a semi-final spot, and it made for an open, high-scoring contest.
A stronger bench saw St. Anne's take the spoils, hitting an unanswered 1-4 in the closing five minutes to defeat Gusserane, including a combined 1-2 haul from the new arrivals in a triple substitution near the end of the third quarter.
And they will know their fate tonight (Tuesday), as they need St. James' to beat or draw with Shelmaliers in order to qualify for the last four.
Gusserane were dealt a game-changing blow at the start of the closing quarter, shortly after Darragh Doyle had edged them into a 1-15 to 2-11 lead.
Full-forward Adrian Flynn had to hobble off with an injury, forcing them to play with 14 men for three minutes as they had travelled with the bare 15.
Ex-goalkeeper and current mentor, David Kehoe, then joined the fray, if only to occupy the mind of the spare St. Anne's player, and a Graeme Cullen point actually widened their lead to two.
However, wing-back Mikey Fogarty had been keen to join the Wexford District side's attack all evening, and he got on the end of a move featuring Jack Murphy and Finn O'Driscoll in the 52nd minute to drive a low left-footed shot into the corner of the net (3-11 to 1-16).
Adrian Flynn's cousin, Shane, a new arrival to the club from Westmeath this year, brought the sides level for the third time in a tight second-half, but Gusserane didn't register again.
Fogarty restored the Anne's lead with a good point from a tight angle, before Darragh Furlong blazed over with a goal on his mind from a Liam Rochford pass.
And then it was the turn of those three substitutes to all play their parts in copper-fastening victory, starting when Dylan O'Brien goaled off the ground at the second attempt in the 59th minute after his first effort was parried by Micheál Ryan.
A fisted effort from Aidan Rochford plus an accurate Andy Kennedy kick closed the scoring for the saints who had led by 2-9 to 1-9 at half-time after mounting a strong comeback.
Indeed, Gusserane posted the first 1-3 without reply in the opening five minutes, with the goal arriving after a mere 45 seconds when Darragh Doyle started and finished an intricate handpassing move that also featured Páraic Conway and Adrian Flynn, with the latter providing an unselfish assist to create an easy finish.
Conway picked off three points and gave the final pass for three more in that half, showing the type of form that makes him worth considering for selection by whoever will get the poisoned chalice and takes over the county team.
The accuracy of Mayo man Seán Kelly gradually brought St. Anne's back into it, and two goals inside two minutes near the end of the half gave them the lead for the first time.
Darragh Furlong's net-rippler from a Jack Murphy handpass left them in arrears by the minimum (1-8 to 1-7), with Adrian Flynn responding with a point before Finn O'Driscoll fed Kelly for the second Anne's major.
Kelly (free) and Kevin White widened their lead to 2-9 to 1-9 by half-time, but Gusserane quickly drew level courtesy of Shane Flynn, Seán O'Connor and Adrian Flynn.
Mikey Fogarty and Kelly (free) made it 2-11 to 1-12, only for the O'Rahilly's to kick four points on the trot from Darragh Doyle (two), Seán O'Connor and Graeme Cullen.
Their lack of reserve strength told against them, though, as St. Anne's finished on a high note.
St. Anne's: Paul Brennan; Kevin White (0-1), Tony McDonnell, Barry Roche; Finn O'Driscoll, Kevin Whelan, Mikey Fogarty (1-2); Paul McDonnell, Mark Furlong (capt.); Mikey O'Brien, Liam Rochford (0-2), Kevin Breen; Jack Murphy, Seán Kelly (1-7, 0-4 frees), Darragh Furlong (1-1). Subs. - Aidan Rochford (0-1) for O'Brien (40), Andy Kennedy (0-1) for Breen (40), Dylan O'Brien (1-0) for P. McDonnell (40).
Gusserane: Micheál Ryan; Donal Kinsella, Jamie Sheehan, Eoghan Foran; Jack Burford, Graeme Cullen (capt., 0-1), Tom Foran (0-1); Cillian Kehoe, Ciarán Conway; Darragh Doyle (1-3), Shane Flynn (0-2), Páraic Conway (0-3); Seán O'Connor (0-3), Adrian Flynn (0-3, 1 free), Shane Cullen (0-1). Sub. - David Kehoe for A. Flynn, inj. (50).
Referee: Kevin Kehoe (Our Lady's Island).