Spirited Brackley were stung by a late strike as Altrincham claimed a 2-1 win in the first leg of the Blue Square Bet North play-off clash at Moss Lane.
The Saints had taken the lead through substitute Jefferson Louis’s superb second-half header, but the home side struck twice in the final 15 minutes to win it.
Simon Richman headed Altrincham level before Jake Moult’s stunning volley from the edge of the area sealed the victory.
But it remains all to play for this weekend as Brackley head home to St James’ Park and aim to book a play-off final date with either FC Halifax Town or Guiseley.
Both sides could be left to rue missed chances as Altrincham hit the woodwork four times during a frantic encounter, while Brackley dominated possession for long stages.
But, ultimately, it is the Greater Manchester outfit who will hold the upper hand going into the second leg thanks to Moult’s fine winner.
Brackley had gone into the game on the back of a 4-3 win at Boston United and a third place finish in the regular season.
The Saints were also boosted by the fact they had won 4-1 at Moss Lane on the opening day of the season and they started strongly in the sun.
They had all the early possession, testing the red and white rearguard with a barrage of balls into the box, which Altrincham, to their credit, dealt well with.
And the home side, backed by a sizeable home crowd in party mode, started to come into the game as Nicky Clee’s low fizzed centre narrowly evaded the sliding Reeves.
But still Brackley controlled proceedings and they almost went ahead when Izak Reid fired a free-kick against the left post.
Altrincham’s fervent support were crying out for something to cheer and they almost got it as Richman’s curled effort nearly caught out keeper Billy Turley, who parried well.
Brackley were carrying a threat of their own, through the trickery of Glenn Walker and the set pieces of Reid, the latter again going close with a whipped free-kick.
Walker was causing all sorts of problems for the uncertain home backline and his clever touch round the corner was almost converted by Eddie Odhiambo, who hit the keeper.
But the Saints were extremely lucky to escape just before the break as Altrincham hit the woodwork three times in the same move.
Shaun Densmore smashed the bar with a free-kick, Gianluca Haven hit the left post with the rebound and the ball then came out to Duncan Watmore, who hit the right post.
There was still time for Odhiambo to miss a simple half-volleyed chance before the break, leaving everyone scratching their heads as to how the game was goalless at half-time.
And they were left even more bemused 13 minutes into the second half, as Clee clipped the ball across goal and Damian Reeves’ looped header came back off the bar.
The striker was determined to open the scoring, but he again failed to hit the net moments later, guiding a powerful header into the Brackley fans behind the goal.
Reeves, who had netted 40 goals already during the campaign, was everywhere, but the finish was eluding him as he steered the ball wide.
Brackley made him pay on 70 minutes as Story sent the ball into the box and Louis, on for Marvin Robinson, planted a fine header into the corner of the net.
Altrincham needed a rapid response and they began to bombard Brackley, who couldn’t get out of their own half.
The inevitable leveller came on 77 minutes as Watmore won the ball well in the Saints area and floated in a fine cross for Richman to head past Turley.
Altrincham continued to threaten and centre-back Scott Leather had a good chance with a minute of normal time remaining, but he blazed he shot over the bar.
But the home side had their winner two minutes into added time as substitute Moult smashed home an unstoppable volley.
Altrincham: Coburn, Densmore, Doughty, Richman, Havern, Leather, Lawrie (Moult 74), Boshell (Lacey 79), Watmore (Brooke 84), Reeves, Clee.
Subs not used: Hall, McMillan.
Brackley: Turley, Clifton, McDonald (Nisevic 90), Sharpe, Austin, Walker, Story (Mulligan 79), Solkhon, Odhiambo, Reid, Robinson (Louis 55).
Subs not used: Diggin, Walker.
Referee: Andrew Miller