Celtic leapfrogged Rangers at the top of the Scottish Premier League by beating their arch-rivals 1-0 at home. Joe Ledley\'s 52nd-minute header from Charlie Mulgrew\'s corner was enough for the Bhoys to go two points clear at the summit. The win was Celtic\'s ninth in a row and means they will top the SPL heading into 2012 after trailing Rangers by as many as 15 points at one stage in November. At Celtic Park, the home side made two changes, with Ki Sung-Yeung and Cha Du-Ri making way for Thomas Rogne and Adam Matthews, while Rangers brought in Sone Aluko, Kyle Bartley and Kirk Broadfoot. Celtic were the form team going into the match and started on the front foot, with Carlos Bocanegra having to be alert to head away the danger from Gary Hooper\'s early effort. However, Rangers thought they had taken a seventh-minute lead when Ross Wallace\'s header from Aluko\'s cross was clawed off the line by Fraser Forster. At the other end, Georgios Samaras chested James Forrest\'s cross into the path of Scott Brown, but the Celtic captain saw his weak shot stopped by Allan McGregor. Almost immediately the hosts had the ball in the net when the keeper spilled Hooper\'s fierce strike from 25 yards and Samaras dinked the rebound past McGregor, but the Greek forward had already been flagged offside. Carlos Bocanegra squandered a great chance in the 20th minute, when Jelavic headed a corner towards goal which the American defender somehow turned over the bar from a few yards out. Hooper caused a panic in the Rangers defence when McGregor couldn\'t hold his shot from range, before the dangerous Forrest fired his effort just over from a tight angle. Samaras danced away from Kirk Broadfoot at the start of the second half only to see his effort cleared away by Bocanegra, before McGregor made a fingertip save to turn Forrest\'s dipping shot over the bar. Celtic were not to be denied, though, and Ledley made the breakthrough in the 52nd minute when he met Mulgrew\'s corner at the back post, in front of Broadfoot, to head past the helpless McGregor. Brown then fired over before McGregor got down low to save a Mulgrew free-kick as Celtic looked for a second goal to kill the match. Rangers were lacking in attack and Jelavic squandered a rare chance when he volleyed over the bar from Kyle Lafferty\'s headed knock down. Celtic were dealt a blow in the 77th minute when Beram Kayal was stretchered off to be replaced by Ki after a collision with Lee McCulloch. The Rangers midfielder was soon replaced by Maurice Edu, while Wallace made way for David Healy as the Ibrox side looked but failed to find a way back into the game. Draws aplenty Elsewhere, St Johnstone defeated Kilmarnock 2-0, St Mirren and Dundee United drew 2-2, Aberdeen and Hearts ended goalless, and Pat Fenlon picked up his first point as Hibernian boss in a 1-1 with Inverness Caledonian Thistle.