There was little between the teams in the opening minutes, Hibs displaying a lot of neat one-touch football without being able to open up a well-drilled Saints defence although they did go close when Allan and Stevie Mallan found Daryl Horgan in space. He spotted team-mate Flo Kamberi free but his low cross was superbly cut out by buddies defender Sean McLoughlin.
Steven Whittaker, operating at left back for Hibs, foraged forward, cut on to his right foot and stung the palms of Saints goalkeeper Vaclav Hladky while attending to his defensive duties with a well-timed tackle on Paul McGinn as he threatened to get on the end of Tony Andreu's pass before Ilkay Durmus had goalkeeper Ofir Marciano rising to touch his powerful effort over.
Hibs had lost Tom James to an ankle injury seconds before the interval, Sean Mackie taking his place and allowing Whittaker to return to a more familiar berth on the right. The home side had enjoyed both more possession and territory in that period without scoring but they almost did so seven minutes after the restart.
Allan spotted Hladky was out of position and he delivered a superbly judged shot which found the inside of the back post but, agonisingly for Hibs, it didn't cross the line. Joe Newell was just as unlucky when his downward header found the same piece of woodwork a minute later. Kamberi was on hand to knock home the rebound but the Swiss striker was adjudged offside.
Having survived those scares the Buddies hit back, Mackie coming up with a goal-saving challenge on Andreu before the Saints midfielder unleashed a shot which forced Marciano into an acrobatic one-handed save.
Hibs again threatened to take the lead with 68 minutes on the clock, kamberi's shot saved by the legs of Hladky following a delightful pass from Allan with substitute Christian Doidge unable to get any meaningful contact on the rebound/
The home fans were just about to settle for a disappointing draw when, with five minutes left, the dancing feet of Allan brought them the goal they'd been looking for, the midfielder driving into the penalty area as he shifted the ball onto his right foot before firing a low shot beyond Hladky.
Doidge should have made iit two when Kamberi's squared pass left him only two yards out and with the goal at his mercy but somehow he managed to avoid making any contact at all on the ball.
Hibs: Marciano, James (Mackie 45) Jackson, Hanlon, Whittaker, Mallan, Vela (Doidge 65) Horgan (Slivka 65) Allan, Jewell, Kamberi.
Substitutes not used: Maxwell, McGregor, Shaw, F Murray.
St Mirren: Hladky, MacPherson, Mackenzie, P McGinn, Magennis, Flynn, McLoughlin, Andreu (Djorkaeff 74), Durmus (Breadner 71), Foley, Mullen (Okiba 55).
Substitutes not used: Lyness, Baird, Erhahon, McAllister.
Referee: Euan Anderson