Ten-man Airdrie took a precious but slender lead into their Championship play-off final second leg clash at Hamilton on Saturday, as Callum Smith returned to haunt his old club.
The winger struck in 56 minutes of a tense first leg at New Broomfield to separate the sides, slightly against the run of play by that point.
There was late drama as defender Craig Watson was sent off in stoppage time for two bookings, but Airdrie held on for the win.
But Rhys McCabe's side won't care, as they try to overcome a play-off hoodoo that struck last season as Queen's Park ran out winners.
From Hamilton Accies' point of view, they have a lot of work to do at home on Saturday, if they are to preserve their Championship status,
Smith gave Airdrie a precious lead 10 minutes into the second half, and Airdrie never really looked back, as Hamilton lacked a cutting edge.
The first half was pretty even, though Hamilton probably slightly edged it.
Connor Smith had a great chance to score for Hamilton, and Airdrie captain Callum Fordyce had a half-volley brilliantly saved.
But Connor Smith had a free kick well saved by Diamonds keeper Josh Rae, as well.
Airdrie emerged as the better side at the start of the second half and took the lead through Smith, which was probably deserved on the balance of play.
Diamonds boss McCabe made one change from the side that beat Falkirk 1-0 on Saturday, with Aaron Taylor-Sinclair coming in for Dean McMaster, who dropped down to the bench.
Hamilton head coach John Rankin kept faith with the side that eventually beat Alloa 5-2 on Saturday.
Lewis Smith had the first chance firing wide of the left post inside two minutes as Hamilton tried to get off to a good, early start.
They went close again in eight minutes when Dylan McGowan tore down the left and set up Connor Smith, but his angled shot flew inches past the left post.
A neat move ended with Lewis Smith trying to beat Josh Rae from an acute angle on the right bye-line in 14 minutes, but the keeper was up to it.
Airdrie's first real chance came in 21 minutes on the counter-attack, but Adam Frizzell fired well over from just outside the box.
Airdrie nearly scored in 31 minutes when Craig Watson's cross from the right picked out Callum Fordyce and his half-volley was clawed over the bar by Jamie Smith.
Connor Smith tried his luck with a free kick from about 23 yards, but Rae saved well at the right post.
Devenny had a good chance to open the scoring for Airdrie in 50 minutes, but fired over, after Dan O'Reilly had blocked Gabby McGill's shot.
Sub Matty Shiels had the ball in the back of the net with an acrobatic overhead kick in 53 minutes, but an offside flag had gone up moments before.
But Airdrie took the lead in 56 minutes when Callum Smith weaved his way down the left and cut inside before slamming a low shot into the left corner.
Airdrie went close to doubling their lead in 63 minutes but Charlie Telfer's shot was deflected into the arms of Smith in Hamilton's goal.
Smith went on a run through the middle for Airdrie in 78 minutes, but O'Reilly did well to block his shot with his face.
The Diamonds tried again in 89 minutes but Smith this time fired over the bar.
There was drama in stoppage time as Craig Watson was sent off for a second booking.
Hamilton nearly took advantage straight away from the free-kick, but O'Reilly's header was touched onto the bar.
But Airdrie went close to doubling their lead a Frizzell's shot was deflected narrowly wide of the left post.
AIRDRIE: Rae, Watson, Fordyce, Taylor-Sinclair, Ballantyne, Frizzell, McCabe, Devenny (Telfer, 56), McGill, Smith (Stanway, 90), Gallagher (McGregor, 84).
Subs (not used): Jamieson (GK), Kouider-Aissa, Fellows, McMaster, Deveney, Byrd.
Booked: Smith (52), Ballantyne (68), Watson (86)
HAMILTON: J. Smith, Tumilty, McGowan, O'Reilly, Mimnaugh, De Bolle (Spence, 66), Martin, C. Smith, Zanatta (Shiels, 46), Winter, L. Smith (Tiehi, 80).
Subs (not used): McFarlane (GK), Easton, Owens, Sparrow, Stephenson, Morgan.
Booked: C. Smith (43), Shiels (72)
Referee: Steven Kirkland.
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