Rangers went top of the table with a 2-0 home win over Dundee United courtesy of first-half goals from Steven Naismith and Barry Ferguson on Saturday.
They have 44 points from 19 games, while champions Celtic, whose match against Motherwell was postponed following the death last weekend of their former player Phil O'Donnell, are second with 43 from 20.
Naismith put Rangers in front after nine minutes with a downward header from Chris Burke's cross. Captain Ferguson headed home another Burke cross five minutes before the interval.
Rangers could have added another goal but Kris Boyd's penalty was saved in the final minute.
Ten-man Hearts drew 1-1 with Kilmarnock after having Calum Elliot sent off in the 36th minute for his second bookable offence.
Lithuanian Andrius Velicka equalised for the home side after the first-half opener from Kilmarnock's Paul Di Giacomo.
Inverness Caledonian Thistle romped to a 3-0 win over Gretna with Romanian striker Marius Niculae scoring twice.
St Mirren beat Hibernian 2-1 while Falkirk drew 0-0 with Aberdeen despite having Scott Arfield sent off.
Meanwhile, Rangers have revealed they could rebuild Ibrox in an ambitious project to increase capacity and regenerate the area around the stadium.
The club may seek to expand their home to a 70,000-capacity arena, according to reports.
In a statement, Rangers confirmed: "The club would like to inform its fans that it is currently assessing a number of proposals for the development and regeneration around Ibrox."
Celtic goalkeeper Artur Boruc (27) has signed a new contract to keep him at Parkhead until 2011 and end speculation about his future.
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