Celtic were far from their flowing best on Saturday evening but got the job done at St Mirren after falling behind.
Yang Hyun-jun was the star man, capping an energetic display with the decisive finish, but the winger is now away with South Korea for the Asian Games.
His absence will mean a reshuffle but Martin O’Neill may be reluctant to shift Camilo Duran out wide again after a run of three goals and two assists in three games at centre forward.
Of the six players arriving in the final 48 hours of the window only two have been used from the bench so far and it could be that Sebastian Tounekti is the safe choice to replace Yang.
Striker Kasper Hogh and left-back Kieran Tierney are also in contention after brief spells out injured.
The champions can expect to face another side who focus on possession and playing through the phases as St Johnstone hunt a third win on the bounce at McDiarmid Park.
Three of Josh Fowler’s four goals have come in Perth, while local lad Taylor Steven caught the eye with his crossing from the right in victory over Hibs.
Centre-backs Cheick Diabate and Zach Mitchell are a no-nonsense pair who will put their heads where it hurts, although Saints are yet to keep a league clean sheet.
O’Neill was last in Perth as a manager 25 years ago but you don’t have to go back very far for the most recent upset, given a home win over Celtic in April 2025 was among the rare moments of joy in a season that ended in relegation for St Johnstone.