St Mirren slipped into the relegation play-off spot after a defeat to Dundee at Dens Park.
An early first-half goal from Joe Westley was enough to secure the points for the Dark Blues to see them move six ahead of Saints who dropped into 11th after Kilmarnock's win over Dundee United.
Interim manager Craig McLeish was forced into three changes with Alex Gogic suspended and Declan John and Jonah Ayunga missing out through injury. Jayden Richardson, Scott Tanser and Roland Idowu came in to replace them.
The Buddies were the team pressing the game in the early stages, but it was Dundee who fashioned the first opportunity to test the goalkeeper on 10 minutes. Yan Dhanda was allowed time and space to drive forward and he sent a low effort into the arms of Ross Sinclair.
The hosts got themselves in front two minutes later. Richard King's slack back pass was pounced upon by Simon Murray. He fed it to Cameron Congreve who worked his way out to right before sending a cross that met Westley. The attacker flicked into net via a nick off the far post. Dundee almost had a second when a Dhanda cross came off the head of King and crashed off the bar.
There was a brief VAR check for a St Mirren penalty four minutes before the interval when O'Hara looked to be impeded by Tony Yogane, but nothing was given.
Saints showed a renewed sense of urgency at the beginning of the second 45. Mikael Mandron struck into the arms of Jon McCracken, while Richardson forced a strong save from the Dundee stopper two minutes later with a powerful shot from 20 yards.
Mandron came agonisingly close to drawing the Buddies level on 57 minutes. The forward got himself on the end of an Allan Campbell cross, but nodded just by the far post.
With 20 minutes to go, Idowu did brilliantly to beat his man on the left and keep the ball in at the byline. He made his way into the box and had O'Hara as an option but elected to go alone and fired into the side net. Idowu then fired into the arms of Dundee's substitute goalkeeper Kieran O'Hara, who had to replace the injured Jon McCracken, three minutes later.
Saints introduced Conor McMenamin, Marcus Fraser and Jake Young as we searched for a leveller, but it was Dundee who almost grabbed a second on the counter in the first of seven minutes of injury time. Illmari Samuels' cross met the head of fellow sub Ashley Hay with Sinclair doing brilliantly to turn it behind.
Full-Time: Dundee 1-0 St Mirren
St Mirren: Sinclair, Richardson, King, Freckleton, Tanser (Fraser 84), O'Hara (c) (McMenamin 80), Devaney, Campbell, Phillips, Idowu (Young 84), Mandron
Subs Not Used: Tamosevicius, Duff, McMillan, Falconer, Calvin, Douglas
Dundee: McCracken (O'Hara 67), Halliday, Astley, Graham, Wright (Samuels 88), Hamilton, Dhanda, Westley (Hay 75), Congreve, Yogane (Koumetio 88), Murray (c) (Robertson 75)
Subs Not Used: Reilly, Cotterill, Bevan, Jones
Referee: Steven McLean
AR1: Chris Rae
AR2: Gordon McCabe
VAR: Nick Walsh
