Ally McCoist's Rangers side ran out comfortable 3-0 winners at Hearts as Sone Aluko's free-kick and Andy Little's header put the visitors in a commanding position by half time.
Aluko's foul on David Templeton gave Hearts an opportunity to pull one back from the penalty spot, but Craig Beattie blazed over the bar and Little added his second of the game just before full time as Rangers extended their advantage over third-placed Motherwell to 11 points.
In the early kick-off Dundee United got the better of St Johnstone 2-0 at McDiarmid Park and leapfrogged their opponents into fourth position in the process, thanks to goals in each half from Scott Robertson and John Rankin.
Robertson gave the visitors the lead in the 36th minute and St Johnstone's task was made even more difficult by the sending off of Francisco Sandaza for a second bookable offence just before the hour. Rankin then compounded a miserable afternoon for the home team as United wrapped up all three points with a goal on the stroke of full time.
At the Caledonian Stadium home side Inverness CT were undone by two own goals as they went down 2-0 to Aberdeen.
Roman Golobart put through his own net at the start of the second half and Kenny Gillet joined his team-mate on the scoresheet - although in a manner neither player would have wanted - in the 89th minute as Craig Brown's team took all three points to move up to seventh.
Andy Kirk's late header salvaged a point for bottom-of-the-table Dunfermline at St Mirren as the two sides played out a thrilling 4-4 draw.
Nigel Hasselbaink opened the scoring inside four minutes as St Mirren took the lead, but Jordan McMillan levelled for the away side. Steve Thompson's first career hat-trick saw the home team into a 4-2 lead, but goals from Liam Buchanan and then Kirk ensured a hard-earned point for Dunfermline.