Leaders Rangers came from a goal down to beat Kilmarnock 2-1 in the Scottish Premier League yesterday and city rivals Celtic beat Motherwell 4-2.
Kilmarnock took a surprise lead after nine minutes when defender Frazer Wright pounced after hesitation from Rangers keeper Allan McGregor and forced the ball home from six metres.
However, Rangers recovered in the second half and levelled when Kris Boyd blasted a 61st minute penalty beyond keeper Alan Combe.
He then turned to crash a fierce 15 metre shot past Combe to put Rangers 2-1 ahead on 63 minutes.
Celtic romped to a 4-0 half-time lead at Motherwell with Greek striker Georgios Samaras hitting a double and Shaun Maloney and Scott McDonald getting the others.
However, Motherwell pulled a couple of goals back after the interval through John Sutton and David Clarkson.
St Mirren won 2-1 at Inverness Caledonian Thistle, Hibernian beat Dundee United 2-1 and Falkirk inflicted a 2-1 defeat on Hearts. Hamilton Academical managed a surprise 2-1 win at Aberdeen.