Airdrie's Scottish Cup run is over as 10-man Championship side Partick Thistle edged them out 1-0 at Firhill.
The Diamonds started strongly but their work was undone by a Brian Graham goal before the half-hour mark. Thistle proceeded to dominate and Scott Tiffoney hit the post.
Referee David Munro made a controversial decision to send Jags centre-back Tunji Akinola off and it handed Airdrie a way back into proceedings.
But they couldn't find a way to goal and lacked a cutting edge, despite a workmanlike performance.
Ian Murray's men were seeking progression to the fifth round for the first time since 2009 but the home side's nine-year record of not losing a Scottish Cup tie against teams below the Premiership was maintained.
Airdrie didn't change their XI from the team that beat Falkirk 3-2 in League One last week. They had racked up five wins in succession prior to coming to Firhill.
Thistle manager Ian McCall meanwhile opted for striker Zak Rudden in attack, despite the forward's decision to sign a pre-contract with Dundee before the match.
Murray's men started in relentless fashion and never gave Thistle a minute of peace. Scott McGill slipped in Callum Smith on five minutes but his effort was hacked away.
Then Adam Frizzell raced through on goal eight minutes but his shot was tame, despite options either side of him.
Despite their good start, a sharp reminder was fired to Airdrie on 22 minutes that they had to score. Cammy Smith won the ball in midfield and teed up Rudden for a good chance, but Diamonds stopper Max Currie made a big save with his foot.
Two minutes later and Graham made sure Airdrie paid. Smith was behind the away defence and handed the Jags striker a tap-in as first blood was drawn.
Thistle had taken control and Tiffoney's shot cannoned off the post on the half-hour mark as they sought a second. Rudden's header on 37 minutes meanwhile was harmless and easily gathered by Currie.
Ross Docherty was the latest Thistle player to test Airdrie keeper Currie and he had to be alert to the midfielder's 41st minute blast, which stung his palms and deflected wide.
After a strong opening, Murray's men were hanging on as half-time approached. But they were handed a big boost on 50 minutes as referee Munro dished out a red card to Akinola.
Slack play from the home side allowed Jordan Allan in but the Thistle defender appeared to get in and win the ball. Munro saw differently and sent him off for a last-man tackle, angering the home crowd.
After this it allowed Airdrie to pile on more pressure. They certainly had more possession and Dylan Easton's shot from 20 yards on 59 minutes forced Jags keeper Jamie Sneddon into a save.
Keith Watson was next to have a go but his header sailed over on 65 minutes. While the League One team did have plenty of the ball, they had to start doing something with it.
McCall's side were still dangerous and Graham almost had a second 16 minutes from time, Currie reacting to palm his chested effort away.
The need for an Airdrie goal was becoming more urgent and Sneddon made a smart stop to deny the Diamonds' after three efforts in quick succession at the back post.
Frizzell tried again on 85 minutes but his effort smashed the side-netting. Airdrie's efforts now fully turn towards League One and promotion to the Championship.
Partick Thistle XI: Sneddon, McKenna, Akinola, Mayo, Holt, Smith (Docherty, 60) Bannigan, Docherty, Tiffoney, Graham, Rudden (Hendrie, 52).
Subs: Cervantes, Crawford, Turner, Hendrie, Murray, MacIver, Bell, Stanway.
Booked: Rudden, Akinola (red).
Airdrie XI: Currie, Fordyce, Watson, McCabe, Walker, Agnew, McGill (77, Gallagher), Frizzell, Smith, Easton, Allan.
Subs: Cantley, Gallagher, Ritchie, McDonald.
Booked: Watson.
Attendance: 2895
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