Motherwell and St Mirren fans briefly clashed on the pitch after Ross Tierney scored a stoppage-time equaliser for the visitors in Paisley.
Alex Gogic looked to have scored a debut winner for St Mirren when he headed home in the 81st minute of a close cinch Premiership encounter 24 hours after moving on loan from Hibernian.
But Tierney finished high into the net after fellow substitute Kaiyne Woolery robbed Richard Tait on the by-line and cut the ball back.
A number of fans of both clubs encroached onto the pitch in the corner and two traded punches before moving back into the stands.
Motherwell had enjoyed the better of a tight first half before both goalkeepers made decent saves in a livelier second period.
Loan signing Jordan Jones also made his St Mirren debut after Jamie McGrath went the other way to Wigan. Tait celebrated signing a one-year contract extension by getting a recall at left-back in place of the injured Scott Tanser.
Motherwell manager Graham Alexander made a rare deviation from his 4-3-3 system. Well lined up in a 3-4-2-1 formation with Sean Goss and Callum Slattery playing in more advanced midfield roles.
Most of the first-half attempts at goal came from Goss, who was twice off target from long range and forced two saves from Jak Alnwick from closer in.
St Mirren struggled to get going in an attacking sense, not helped by centre-forward Eamonn Brophy pulling up injured midway through the first half. Gogic came on, with Connor Ronan pushing further forward and Greg Kiltie leading the line.
Gogic had St Mirren’s best first-half opportunity but Stephen O’Donnell diverted his half-volley wide.
Motherwell also suffered an injury blow before the break when Liam Shaw went off with a head knock. Tierney came on and Goss dropped back.
The Motherwell substitute had a good chance just after the break after being picked out by O’Donnell on the edge of the box. Alnwick stopped his first effort and the Irishman failed to get a decent connection on the rebound.
Liam Kelly was finally called into action just before the hour when Jones’ free-kick found Tait at the back post and the Motherwell goalkeeper showed excellent reactions to keep out a stooping header.
Saints brought on Lee Erwin to play up front in his first appearance for four months.
Jones had a let-off when he put in a clumsy challenge on Slattery just inside the box – referee Euan Anderson penalised the Motherwell man for handling the ball when he landed on the ground.
Both sides were now attacking with more urgency. Slattery played Kevin Van Veen in behind with a superb pass but the angle was not easy and Alnwick blocked the Dutchman’s powerful drive.
St Mirren right-back Marcus Fraser found himself in space in the Motherwell box but curled over with his left foot and Kelly did brilliantly to tip over substitute Ryan Flynn’s 25-yard strike.
The hosts netted from the resulting corner. Gogic rose highest to meet Ronan’s delivery and directed a powerful header in off a post.
Motherwell threw Bevis Mugabi up front and the defender forced a decent stop from Alnwick with a volley before being floored as the keeper came out to meet a high ball. Anderson waved away penalty appeals.
Saints were on their way to a fourth win from four matches in 2022 until Tierney struck and Alnwick saved from van Veen as Motherwell threatened a turnaround.