Football’s fine margins were celebrated and mourned on Sunday afternoon at the Simple Digital Arena; tears of relief from St Mirren as they retained their Premiership status and tears of despair as Dundee United were confined to a fourth successive season in the Championship.

An anxious and nervous two-legged affair had to be decided on penalties after the tie was poised at 1-1 after 210 minutes of football between the teams. From the resultant shoot-out, United missed all four penalty kicks, with St Mirren keeper Vaclav Hladky the hero of the afternoon for the hosts as he saved three of those efforts.

The conversion from Paul McGinn and Mihai Popescu meant that the sclaffed effort from Mateo Muzek which came off the post was redundant after Hladky saved Callum Booth’s effort. No sooner had Hladky denied Booth than the pitch was swarmed with St Mirren supporters with the goalkeeper missing in action under a sea of bodies as the tension within the stadium finally evaporated.

If the two-pronged affair was a stultifying encounter given the magnitude of what was at stake there was a feeling that St Mirren were well worth their prolonged stay in the top flight. The Premiership side had a fair bit of momentum at their backs going into the playoff after emerging from the split unbeaten but there was a sense of grievance too at the manner in which they had found themselves going behind midway through the opening period.

Ironically, given how the afternoon ended, Nicky Clark had opened the scoring for the Tannadice side from the spot after Jack Baird had been harshly judged to have blocked a Booth cross with his hand by referee John Beaton.

It was a lead that lasted just three minutes before Danny Mullen restored parity. If United’s afternoon did not get much better after that then neither did Beaton’s.

St Mirren played out the final minutes of extra-time after a dismissal for Duckens Nazon for a foul on Mark Connolly. Nazon had arrived for the seven minutes of regulation time but had an intriguing duel going on with Connolly; his straight red seemed harsh, particularly given that it came on the back of Connolly, who had already been booked, cementing the player as he ran at the United defence in the first period of extra-time.

If that was enough to get the hackles up for St Mirren there was also the small matter of a first-half Kyle McAllister goal that was wrongly chalked off for offside.

On the balance of play it was difficult not to feel that Kearney’s side were worthy of hanging on to their top flight status. Since the turn of the year the affable Irishman has rebuilt his playing squad and has been successful in turning around the fortunes of a team whose slide into the Championship had seemed like an inevitability in the darkest months of winter. Just three defeats from the last 15 games would have given them a sense of belief as they headed into these taut play-off games.

It will be interesting to see what happens next. Kearney has been linked with a move back to Northern Ireland over the last few months but if St Mirren are to build on the foundations they have set in the latter half of the campaign then maintaining some kind of continuity has to be key to that.

For United, it is a damning result.

The lack of conviction as the game went to the penalty shoot-out seemed reflective of a team who were spent. But the longer they remain in the Championship the harder it gets to move out of.

They actually started this game in Paisley fairly brightly.

For the first time since its inception a decade ago, St Mirren sold out every ticket for the game with the nerves and anxiety in the stands quickly radiating onto the pitch.

The game was still in its infancy when St Mirren defender Gary Mackenzie sent an intended pass towards McGinn but which was intercepted by Jamie Robson. The move came to nothing but was indicative of the sense of the nerves on both sides the precarity and finely balanced nature of the tie.

It took until United netted from the spot and Mullen levelled before the game started to open up a little. Lee Hodson and Mullen combined before the industrious Cody Cooke just missed connecting at the back post before McAllister lashed an effort into the side-netting.

Jack Baird thought he had one it for Saints in the latter stages of the game with a lashed effort from distance while Paul McGinn had brought out an acrobatic stop from Benjamin Siegrist in the United goal.

Ultimately it all came to the drama and lottery of penalties before the celebrations and recriminations began.