Celtic's miserable season hit a new low with a first home defeat to St Mirren since 1990 as the in-form Buddies beat the soon to be deposed Scottish champions 2-1 on Saturday. A first league defeat to anyone other than Rangers leaves Celtic still 23 points behind their Glasgow rivals, who are closing in on their first top-flight title for 10 years. Kristian Dennis fired in the opener for St. Mirren in the 18th minute before Odsonne Edouard levelled just after the half-hour mark. However, Ilkay Durmus restored Saints' lead in the 37th minute, with more questions around centre-back Shane Duffy's defending as the Ireland international made another glaring error. Celtic failed to turn things around in a goalless second half and questions will be asked over how long manager Neil Lennon can remain in charge with the Hoops now clinging on to second place. The club's long-serving chief executive Peter Lawwell announced on Friday he will be stepping down at the end of the season, but the pressure is building on Lawwell to make a change and salvage a place in next season's Champions League qualifiers. Aberdeen are now five points adrift of Celtic after being held 0-0 by in-form Livingston. Hibernian moved to within a point of the Dons in fourth with a comfortable 2-0 win at Dundee United thanks to goals either side of half-time by Darren McGregor and Martin Boyle. St Johnstone came from 2-0 down to beat Kilmarnock 3-2 at Rugby Park. kca/mw