A LATE strike from substitute Ross Caldwell sent the Pars spinning to a desperately unlucky defeat at St Mirren tonight (Tuesday).

Sent on at half-time as they trailed to Lewis Spence's ninth-minute strike, Caldwell levelled four minutes into the second half before scoring the goal to inflict League Cup heartache.

It was tough on Athletic, who matched their Premiership opponents for long spells but can hold their head high after a display that was appreciated by their travelling support.

Jim Jefferies made two changes from Saturday's defeat of Airdrieonians. Faissal El Bakhtaoui and the injured Ross Drummond missed out and we replaced by Ryan Williamson and Ryan Thomson. New signing Stuart Urquhart was given a seat on the bench along with Andy Stirling, who had yet to feature in a competitive match since signing from Stranraer due to injury.

After a confident opening where they looked to capitalise on the nerves of a home side who have lost their opening three league games, the Pars made a dream start by taking the lead on nine minutes. Ross Millen's floated free-kick into the area was poorly headed clear by the Buddies defence and Spence was on hand to send an excellent low drive into the bottom corner of Marian Kello's net.

The Pars continued to look confident in possession but after Michael Moffat sent a shot wide of the near post, they had a huge let off on 23 minutes.

A ball in from the left wasn't headed far enough out by Gregor Buchanan and after picking up the loose ball and making space for himself inside the box, Adam Drury's powerful shot from eight yards rattled the junction of post and crossbar.

The Saints began enjoying more possession but the Dunfermline defence restricted them to few sights at goal.

There was a lack of conviction about Tommy Craig's team and indeed it was the Pars who looked threatening, with the presence of Gozie Ugwu and Moffat unsettling St Mirren's defence.

And the forward duo caused panic as Ugwu's flick from a long ball for Moffat to chase saw hesitation between Marc McAusland and Kello, leading to a Pars corner.

Lewis Martin though had to be called upon to produce an outstanding tackle inside the box to deny John McGinn a shot at goal as the half drew to a close before Ryan Scully was called into his first real action in first half stoppage time.

A stinging Gregg Wylde drive was spilled by Scully but the loose ball was poked wide.

Saints boss Craig made a double switch at the interval, replacing Isaac Osborne and Stephen Thompson with Calum Ball and Ross Caldwell in a bid to turn the game around.

And just four minutes into the second half, it paid dividends. Caldwell picked the ball up on the left and, after cutting into the area, sent a shot beyond Scully.

The Pars reacted well and Kello's legs denied Ugwu as he was sent clear in the box to the right of goal, before Moffat sent a 20-yarder over the bar.

The game was becoming more and more open and Scully kept Pars level with a wonderful block to deny Ball after Lewis Martin had done well to intercept a dangerous through ball.

Scully was again called into action to deny McLean, but the Pars weathered a spell of pressure to forcea couple of corners midway through the half that Kello comfortably dealt with.

They created a decent half chance when Falkingham got a toe to Moffat's left-wing delivery but the ball went over the bar.

Andy Geggan then headed wide from a Millen corner as they continued to pose questions of the St Mirren defence.

They created an even better chance on 76 minutes. A superb cross-field run by Ryan Williamson saw the full-back find Moffat, who dinked a delightful ball into the box for Falkingham. He controlled and turned well but his shot ended just inches wide of target.

But there was late heartbreak as Saints grabbed a lead they barely deserved after the ball found its way to Caldwell 12 yards out to place the ball beyond Scully.

The Pars again rallied and put the Premiership side under pressure in the closing minutes.

Despite forcing late set-piece opportunities, their best chance fell in stoppage time as Millen saw a shot blocked at a corner as the Pars exited the competition - but only after making the 2013 League Cup winners sweat.

St Mirren: Kello, Naismith, McAusland, Plummer, Osborne, McGinn, Drury, Thompson, Tesselaar, McLean, Wylde.

Subs: Ridgers, Teale, Reilly, Ball, Kelly, Caldwell, Brown.

Goals: Caldwell (49, 81).

Pars: Scully, Williamson, Millen, Martin, Buchanan, Geggan, Thomson, Spence, Moffat, Falkingham, Ugwu.

Subs: Goodfellow, Byrne, Forbes, Urquhart, Smith, Stirling, Page.

Goal: Spence (9).

Referee: Steven McLean.

Attendance: 1931.