St Johnstone manager Steve Lomas has backed goalkeeper Peter Enckelman to respond from his midweek howler in Sunday's Clydesdale Bank Premier League clash with Celtic at McDiarmid Park.
Enckelman's poor clearance led to Ryan Jack's goal from the halfway line as Aberdeen beat Saints 2-1 on Tuesday night. But the Finn has also been a key protagonist in some of fourth-placed Saints' more memorable results this season, including a 1-0 win at Celtic under Lomas' predecessor Derek McInnes.
"Peter's done brilliantly in other games and saved us at Hearts, saving a penalty to get us three points," said Lomas.
"He saved a penalty early on at Celtic Park earlier in the season and Derek will tell you that's probably the catalyst why they went on to get three points, because if Celtic score early against you at Celtic Park it's normally not a good sign."
Lomas' spell at St Johnstone began with a 0-0 draw against Rangers, before wins over Hibernian and Hearts.
Saints now take on Celtic seeking to bounce back from Lomas' first losses in charge, last Saturday's 3-0 defeat to Motherwell and the midweek setback against the Dons.
Lomas has been without striker Francisco Sandaza (thigh), captain Jody Morris (hamstring) and his fellow midfielder Kevin Moon (illness) in recent matches.
Defender Frazer Wright (thigh) and striker Cillian Sheridan (hamstring) have also been missing.
At least some of the key absentees may be available on Sunday, but Lomas declined to name names.
"We're taking stock at the minute and hopefully will have a couple back," he added. "We'll make a decision tomorrow."