Linfield were beaten in a six-goal thriller by Tommy Wright’s St Johnstone on Saturday.
The Blues got off to a flier at Windsor Park as new boy Shayne Lavery fired them in front after only two minutes as he dispossessed goalkeeper Zander Clark before slotting home.
The visitors missed a penalty before Danielo Swanson drew the sides level before the break.
Callum Hendry headed the Saints in front with 20 minutes to go.
Ali McCann made it 3-1 before Lorcan Forde pulled a goal back for Linfield.
But right at the end St Johnstone captain Jason Kerr headed in at the back post.
Glenavon produced an excellent performance against more Scottish Premiership opposition as they beat Hearts 2-1 at Mournview Park.
Stephen Murray fired the home side in front on 37 minutes as he took advantage of a Harry Cochrane error.
Matthew Ferguson doubled Glenavon’s lead just after the hour when he headed home Andy Hall’s corner.
Sean Clare managed to pull a consolation goal back for the visitors with four minutes to go.