A week of soul searching at Celtic has commenced and three points in Perth are a necessity. St Johnstone held the Premiership champions to a 0-0 draw last time out but they are under new management in Craig Levein.
But he is no stranger to landing a shock blow on counterpart Brendan Rodgers either. The Parkhead boss has been left calling for quality after their Champions League campaign was ended midweek by Lazio.
It's not exactly been plain-sailing on the domestic front either. They left for the Eternal City off a 1-1 draw at home to Motherwell.
Crucially, they still hold an eight-point gap over Rangers and they can make that 11 in Perth. Saints will have ambitions of their own though in their bid to move away from the bottom section of the league.