St Mirren made two changes from the team that knocked Rangers out of the Betfred Cup in midweek. In came Erwin and Ilkay Durmus, with Obika and Brandon Mason dropping to the bench.

St Johnstone also freshened things up after their penalty shoot-out victory over Dunfermline Athletic in the same competition. Out went Shaun Rooney, Callum Booth, Liam Craig and Chris Kane to be replaced by Jamie McCart, Danny McNamara, Craig Conway and May.

It was St Mirren who had the first real chance of the game after 14 minutes, Erwin's shot from the edge of the box pushed away by Zander Clark.

It was St Johnstone, though, who went in front with their first chance after 22 minutes. Joe Shaughnessy was adjudged to have fouled David Wotherspoon as they contested Tanser's ball. Goalkeeper Jak Alnwick got across to May's penalty but could not stop the shot from squirming under him and into the net.

The home side drew level seven minutes before half-time. Marcus Fraser's cross was headed out to Erhahon whose shot bounced into the ground and beyond Clark.

But the celebrations were short-lived as St Johnstone quickly got their noses back in front. Shaughnessy's poor clearance fell to Tanser and he guided a smart finish into the corner of the net.

That was not the end of the first-half action, with Kerr shown a straight red card for a wild lunge on Durmus.

St Johnstone came close to extending their lead early in the second. Conway's cross was met by Liam Gordon and Alnwick did well to touch the defender's header over the crossbar.

St Mirren drew level for a second time eight minutes before the end. Substitute Kyle McAllister sent over an enticing cross and Erwin stretched to head beyond Clark.

McAllister then put a free-kick right on to Obika's head for what proved to be the winning goal five minutes from time.