Celtic rebel Stilian Petrov, who has been agitating for a move out of Parkhead, illustrated his value to the Glasgow giants with the second goal in a 2-0 win over St Mirren.
Stephen McManus opened the scoring for Celtic before the Bulgarian captain made sure of the points to give Gordon Strachan’s side a deserved victory against last season's First Division champions, who had began the day as Scottish Premier League leaders.
Celtic started the match strongly against the Paisley team and Irish international Aiden McGeady came close to opening the scoring in the 12th minute when his right-foot strike from 20-yards beat St Mirren goalkeeper Chris Smith only to strike the left-hand post.
McGeady then threaded a pass through the St Mirren defence in the 18th minute to put Maciej Zurawski through on goal but Smith was sharp off his line to block the Polish striker's effort.
However, in the 28th minute an error of judgement by the visitor’s keeper handed Celtic the lead.
Smith decided to leave his line to try and collect Japanese international Shunsuke Nakamura's corner but got nowhere near the ball allowing McManus, Celtic's captain in the absence the injured Neil Lennon, the simple task of heading into the empty net from 12 yards.
In the 33rd minute Zurawski should have doubled his side's lead when Nakamura's pass put him one-on-one with the keeper but he hit straight at Smith who blocked with his legs.
Celtic continued to press for a second goal after the half-time break but St Mirren, superbly marshalled by their 41-year-old centre-half Andy Millen, were proving difficult to break down.
Despite rarely venturing forward St Mirren's Kirk Broadfoot should have tested Celtic's Polish keeper Artur Boruc in the 58th minute when he headed Simon Lappin's free-kick wide from 10 yards.
At the other end a Nakamura free-kick from 25 yards had Smith scampering along his line as the ball flew inches wide in the 60th minute.
But in the 65th minute Celtic doubled their lead after McGeady collected the ball 30 yards from goal and slid it through to Petrov, who had made a great run into the penalty box, and from eight-yards the Bulgarian hit a low right-foot shot which beat Smith at his near post.
St Mirren nearly reduced the gap in the 70th minute when Lappin’s free-kick from 25 yards crashed off the crossbar. John Sutton, younger brother of former Celtic striker Chris, could not convert the rebound, heading lamely into Boruc's hands.
Scottish international striker Kenny Miller was still looking for his first goal in Celtic colours and he missed a glorious chance in the 80th minute.
A deep cross from Craig Beattie, who had replaced Zurawski six minutes previously, found Miller unmarked at the back post but from four-yards he screwed his shot wide.
