Celtic opened up a five-point lead at the top of the Scottish Premier League with a hard-fought 2-0 win at St. Mirren. Neil Lennon\'s side struggled for long periods, but James Forrest broke the deadlock deep into the second half before Scott Brown\'s late strike wrapped up the points and increased Celtic\'s advantage over second-placed Rangers. The reigning champions can reduce the gap back to two points if they beat Aberdeen at Ibrox later today. Lennon brought in Korea Republic internationals Cha Du-Ri and Ki Sung-Yueng, as well as Forrest, with Adam Matthews, Emilio Izaguirre and Anthony Stokes all dropping to the bench. Celtic were looking for their 12th successive league win, but the Hoops struggled to find any momentum in the first half. St. Mirren had the first sight of goal when Graham Carey\'s corner was met at the far post by Marc McAusland and the unmarked defender\'s half-volley forced a good save from Celtic goalkeeper Fraser Forster. The visitors responded and Gary Hooper\'s looping drive from 35 yards had Saints goalkeeper Craig Samson scrambling to make a fine save for a corner. Samson made another impressive stop to prevent an own goal from Steven Thompson, who inadvertently headed towards his own net while trying to clear. Those were rare moments of danger from Celtic, however, and St. Mirren nearly took the lead when Carey\'s volley flashed narrowly wide just before half-time. The windy conditions made it hard for both teams, but Celtic seemed more troubled, and it was St. Mirren who took the early initiative in the second half. Dougie Imrie\'s low strike was kept out by Forster before the Celtic goalkeeper made a great save to deny Paul McGowan. Lennon sent on Stokes and Kris Commons in a bid to spark his team into life and it proved an inspired move as Celtic took the lead in the 71st minute. Commons\' free-kick was cleared to the edge of the area and Brown set up Scotland winger Forrest for a powerful low shot past Samson. St. Mirren pushed forward and Forster made a close-range stop from Saints defender Lee Mair following a Carey corner. But Brown sealed the points for Celtic in the 88th minute when he collected a Commons corner and curled his shot past Samson from the edge of area.