Rowan Vine scored 10 minutes from time to hand St Johnstone a 2-1 win over Celtic on Saturday.
Celtic took the lead after just four minutes when Kris Commons pounced on a loose ball inside the box to covert from close range.
The home side improved as the half developed, however, and they were level after 18 minutes when Gregory Tade found a cool finish inside the box.
Commons might have added to Celtic's lead moments later, but his stinging effort just moved high and wide of the crossbar.
The home side enjoyed the better of possession as the half approached its latter stages, but the pair entered the break level.
Liam Craig came close for the home side moments into the second period, but he fired wide before Commons followed suit for Celtic with 20 minutes remaining.
The away side - who could have gone top with a win - enjoyed the better of the chances in the latter stages, but Scott Brown fired their best chance wide late on.
The home side remained a threat, however, and they won it late on courtesy of a powerful strike from Vine.