St Mirren were defeated at The SMiSA Stadium in league action for just a second time this season as the Buddies lost 1-0 to Kilmarnock.
Marley Watkins' first-half strike was enough to secure the points for the Ayrshire side and see them move four points clear of the Buddies in the cinch Premiership and consign Saints to just a second loss in 10 home league matches this season.
There were two changes to the side that lost 2-0 to Hearts at Tynecastle on Saturday. James Bolton came in from the start as did Toyosi Olusanya in place of Thierry Small and the injured Alex Greive.
Saints started brightly and thought they had taken a 14th minute lead when Jonah Ayunga stuck the ball in the net. The forward reacted quickest to Will Dennis' save from Olusanya's strike, but the offside flag was raised. A VAR check confirmed that Olusanya was narrowly offside in the build up to the goal.
Jonah Ayunga's early goal was disallowed for an offside in the build-up (Image: Allan Picken)
But it was the away side that took the lead when Marley Watkins fired them ahead on 25 minutes. The Killie forward peeled away from the Saints defence and slammed high into the net after being slipped in by Matthew Kennedy.
The visitors were in the ascendancy and came close to adding a second when Brad Lyons' good delivery had to be headed clear by Marcus Fraser with Kyle Vassell lurking at the far post. Kilmarnock were then awarded a free-kick in a decent area just outside the Saints box after loose possession saw the Buddies lose the ball and Richard Taylor booked for hauling down Daniel Armstrong. The Killie winger took the free-kick but it deflected wide. VAR checked for a possible penalty for handball, but the check ruled no handball and no penalty.
Saints looked to try and find their way back into the match but all the Buddies could muster before the interval was a Scott Tanser volley from 25 yard that was pushed away by Dennis.
After a fairly uneventful start to the second-half, Saints boss Stephen Robinson made two changes on 64 minutes when he introduced Conor McMenamin and Mikael Mandron for Marcus Fraser and Olusanya. McMenamin almost made an instant impact when he flashed a dangerous ball across the face of goal but there were no takers in black and white to force home.
Stav Nahmani then came on with 15 minutes remaining to replace Ayunga and he too wasn't far away from making a quick impact when he found himself in good space inside the box. He twisted to try and get the shot away but his attempt was well blocked by Corrie Ndaba. Moments later Bolton came agonisingly close to the equaliser when he rose the highest to meet a cross but his header was brilliant saved by Dennis who got a fingertip to it to touch over.
The visitors almost doubled their lead with 10 minutes to go when Brad Lyons' header had to be cleared off the line before Hemming got two powerful hands behind a powerful drive from the edge of the area.
Saints continued to put pressure on in search of a leveller and it looked like it may come six minutes from time when a ball to the back post from McMenamin found Tanser but he somehow couldn't force the ball over the line as the Buddies were beaten.
Full-Time: St Mirren 0-1 Kilmarnock
St Mirren: Hemming, Fraser (McMenamin 64), Gogic, Taylor, Bolton, Baccus, O'Hara (c), Kiltie, Ayunga (Nahmani 75), Olusanya (Mandron 64)
Subs Not Used: Urminsky, Dunne, Small, Flynn, Boyd-Munce, Jamieson
Kilmarnock: Dennis, Mayo, Findlay, Deas, Ndaba, Armstrong (Wright 87), Kennedy (McKenzie 72), Watson, Lyons, Watkins (Dallas 75), Vassell (c)
Subs Not Used: O'Hara, Sanders, Davies, Polworth, Warnock, Mackay-Steven
Referee: Euan Anderson
Assistant Referee: Daniel McFarlane
Assistant Referee: David Dunne
Fourth Official: Ross Hardie
VAR: Steven Kirkland
Attendance: 7,534