By Tom Gott Rangers ensured they kept pace with Celtic at the top of the Scottish Premiership with an emphatic 4-0 victory over St Mirren on Saturday. The visitors came into this one in excellent form, with a 2-0 win over the league leaders in their recent past, but they were nowhere near a match for Giovanni van Bronckhorst’s side. Rangers were ahead after just a few minutes when Antonio Colak finished off a moment of penalty box pinball which stemmed from a fierce strike from Borna Barisic. The left-back’s effort struck the post and found its way to Colak, who was in the right place at the r…