Brad Lyons' header hauled St Mirren above Dundee at the bottom of the Scottish Premiership as they beat the Dens Park side in Paisley.

Trailing their visitors by a point before the game, the home support feared the worst when Ethan Robson put Dundee ahead within the opening minute.

But Danny Mullen soon replied before Lyons turned the game around.

With seven matches to go, it could be a huge three points come the end of the season for Oran Kearney's side.

And, with Hamilton losing to Kilmarnock, St Mirren cut the gap on 10th-place Accies to four points.

Paisley men turn it around

With so much at stake, and a big crowd inside the Simple Digital Arena, it would have been little surprise had the occasion turned into a tense affair. But any notions that these two sides would spend time sizing each other up evaporated within seconds.

Many had yet to settle in their seats before Dundee pushed forward, John O'Sullivan sent an early ball into the box, and Robson drove in his first goal for the club in front of the 1,500-strong travelling support.

The action didn't let up there. Andrew Nelson squeezed through the defence and shot wide as Dundee threatened to go further ahead. But before they could, St Mirren dug in their heels and got themselves back on level terms.

Mullen got the deftest of touches to direct Duckens Nazon's ball across the box past goalkeeper Seny Dieng. It was Mullen's third league goal of the season - all three coming against Dundee.

St Mirren goalkeeper Vaclav Hladky had to save well from Craig Curran and O'Sullivan, and Lyons shot over at the other end as the chances kept coming.

Dundee had probably shaded the first half, and Curran's powerful effort was pushed away by Vaclav as they began the second half with the same attacking intent they had started the first.

But then all their good play, their pressure and their confidence slowly eroded as they went more and more into their shells as the half went on.

Lyons headed in from close range with Dieng getting a hand to it, but the goalkeeper had dived a touch too early and allowed it to pass by him.

And Kearney's side continued on the front foot, holding on to the ball well as Dundee struggled to get out of their own half. Anders Dreyer headed over with the goal gaping after Lyon's shot was deflected, then Genseric Kusunga had to clear Ryan Flynn's shot off the line.

St Mirren had the ball in the net from Simeon Jackson's header, but it was ruled out for an earlier infringement.

A goal would have made the latter stages less nervy, but Dundee struggled to recreate their first-half showing and the hosts saw the game out comfortably enough to leave Jim McIntyre's side as the ones sitting precariously in bottom spot.

Brad Lyon's header proved decisive for relegation-threatened St Mirren

'Kearney gamble pays off' - analysis

BBC Scotland's Chick Young at Simple Digital Arena

The result guarantees nothing in terms of a stay of execution, but it is a massive step towards salvation for St Mirren. This was a gamble that paid off for Oran Kearney. He brought back Danny Mullen and Gary MacKenzie from the wilderness and they delivered big time. Along with Ryan Flynn, they were the best players on the park.

Dundee manager Jim McIntyre had a steely determination as he left the ground with a word of congratulation to the St Mirren chairman, but with the additional comment of "see you again soon". This relegation fight is about as over as Brexit.

'There are no wild celebrations' - reaction

St Mirren manager Oran Kearney: "We all crave that momentum and that springboard to kick forward. The three points today will hopefully give us that.

"We wasted the first half. But I thought the way we got ourselves back into the game was brilliant. There are no wild celebrations. It's more of a tired changing room than an ecstatic one."

Dundee manager Jim McIntyre: "I'm obviously gutted we lost the game, but we deservedly lost it. Once they scored in the second half, St Mirren were the better side. Our reaction was poor.

"That's what happens at this stage of the season, nerves kick in. The players have got to stand up and be counted. The second goal is ridiculous. But it's not done, it's not done by a long shot."