A last-minute Alex Samuel goal salvaged a draw for Morton in a thunderous Renfrewshire derby in Paisley.

St Mirren had taken an early lead through Jack Baird and had survived when Morton were wrongly denied a penalty soon after.

Without a home win in the Championship all season, Saints were just minutes from finally pulling it off.

But substitute Samuel gobbled up the chance after Jamie Langfield parried a Denny Johnstone shot.

Samuel looked offside but the point was just reward for the visitors' excellent second half performance.

It was absorbing right from the first whistle. There was an edge, an aggression and a hunger that came tumbling out in every lusty tackle, legal and otherwise.

St Mirren have toiled badly. Two league wins all season and neither of them at home, a place that has come to resemble a footballing graveyard for Ian Murray's side.

Alex Samuel slots a late equaliser for Morton

Before Morton fetched-up, Saints had lost three on the bounce and that all too familiar racket in these parts in recent years - the sound of agitating supporters - could be heard anew.

Their opponents were the polar opposite. Morton had moved serenely up the table, into fourth on the back of goal after goal from the classy Johnstone, the striker on loan from Birmingham.

Jim Duffy's team had won four in a row in the league and came to Paisley as favourites, but Duffy is too long in the tooth to have thought that this was going to be anything other than a battle, which it duly was.

There was stuff happening on the ball and off the ball, thunderclap tackles and sly elbows. But amid all of this there was an engrossing game with chances and ambition and stuff to warm the bodies of the hardy souls who braved the bitingly cold night.

St Mirren got off to a flyer. Scott Agnew had a fine chance early on but scuffed it wide. Soon after, team-mate, Lawrence Shankland, had a moment but hooked it over.

There was a tempo and a confidence about Murray's team that belied their grim place in the table. And then there was a goal to show for it.

Stefan McCluskey was denied a penalty after Jamie Langfield's challenge

It was fortunate but it was precious. Agnew's corner proved a personal calamity for Grant Adam, with the goalkeeper letting the ball through his grasp and Baird took advantage of the blunder by nodding home.

Every St Mirren fan can give you chapter and verse about their team's vulnerabilities when defending a lead. Time and again this season they have given themselves an advantage only to grow jumpy in defence of it, usually with bad consequences.

So when Morton came back into it, the sense of déjà vu was palpable. There was a scare - a big one - when Stefan McCluskey hit the deck in the box under a challenge from Langfield. It should have been a penalty. Instead, John Beaton gave McCluskey a yellow card.

A fortunate escape for St Mirren - and then there was another. A fine run by Ross Forbes brought a save from Langfield, but still there was work to be done. The ball spun in the air and was heading for the net until Craig Reid pulled off an acrobatic goal-line clearance.

Craig Reid produced a stunning goal-line clearance to preserve St Mirren's lead

The opening half carried on at a cracking pace. Stephen Mallan's wonderful free-kick brought a terrific save from Adam, the goalkeeper pawing the ball away from the top left-hand corner of his goal.

Shankland had a chance quickly after. So, too, the impressive Agnew. It was frenetic stuff and it didn't let up. The chances may not have flowed as freely after the interval but the aggravation certainly did.

It became a scrap to the end between two teams who badly wanted victory. Neither of them got it. With a minute left, and Saints looking nervous, Morton went at them, Johnstone fired in a shot that Langfield pushed straight into the path of Samuel, who tapped it home.

Tumultuous stuff.

St Mirren manager Ian Murray: "I think our initial thought (for the equaliser) is offside, and then you have to go back and look at and think, where's your defence?

"But at the time it looked very bizarre that a striker could be so close in with nobody challenging him and not be offside. I think the pictures prove it's a good couple of yards offside.

"It's another sucker punch, and we take it on the chin and get on with it, but there's been a lot of them recently.

"We don't want to bleat on and blame officials for our league position, that's for sure, but there comes a time where something has to be done."

Greenock Morton manager Jim Duffy: "It would have been a travesty if we'd got nothing from the game.

"We're the away side coming to a side who were in the Premiership last season and we were in League One - there were two divisions separating us last season - and we came here and pretty much dominated the game, on the front foot, and went at them.

"We could have come here and sat in and tried to nick a point - we ended up nicking a point, but not in the manner of a defensive display, in the manner of a positive, attacking display."