Goals from Kris Boyd and Steven Davis allowed Rangers to exact revenge on St Mirren for inflicting their only defeat in the Scottish Premier League so far this season with a 2-1 win at Ibrox.
Saints put a major dent in Rangers' title hopes with a shock win at Love Street in October but failed to pull off a repeat in Glasgow despite a late rally.
Boyd and Davis struck in the opening 10 minutes - and Rangers held on for victory, despite a late Franco Miranda strike, to cut Celtic's lead to a single point before the Scottish champions face Hamilton on Sunday (UK time).
Kilmarnock ended Dundee United's 10-match unbeaten run to add further intrigue to the race for places in the top half of the Scottish Premier League.
Jamie Hamill drove home a penalty with the last kick of a poor first half and David Fernandez scored against his former side during a much livelier second period to seal a 2-0 win for Killie.
United substitute Jon Daly had a penalty claim denied but the hosts held on comfortably to knock the visitors off third spot.
Hearts recorded their third 1-0 victory in a row at the Caledonian Stadium against Inverness thanks to a moment of brilliance by Bruno Aguiar.
The Portuguese midfielder picked up an Andrew Driver pass on the edge of the box and twisted one way then another before unleashing a low drive past Ryan Esson in the 22nd minute.
An injury-time strike from Steven Fletcher rescued a dramatic draw for Hibernian at home to Aberdeen with the last kick of an amazing match.
Defensive lapses looked to have heaped pressure on manager Mixu Paatelainen as his team headed for a third consecutive defeat.
Captain Rob Jones' first-half mistake allowed Darren Mackie the simplest of openers and Zander Diamond's header eight minutes after the interval looked to have sealed all three points for Aberdeen.
However, Jones gave his team some hope and set up a grandstand finish when he pulled a goal back in the 62nd minute.
Despite throwing everything at the Dons in a tense finale, time looked to be running out on Hibs before Fletcher popped up to finally snatch a point.
Michael Higdon's third goal in a week earned Falkirk a battling victory over Motherwell and stretched its unbeaten run to six matches.
After scoring against Hamilton last weekend and at Inverness in midweek, the striker made it three in three matches as the Bairns broke their run of three straight draws.
In a game lacking clear-cut chances, an excellent winner lit up the Falkirk Stadium as Higdon finished off a flowing four-man move to drive home from the edge of the penalty area after 37 minutes.
Falkirk 1 (Higdon 37)
Motherwell 0
Hibernian 2 (Jones 62, Fletcher 90)
Aberdeen 2 (Mackie 40, Diamond 53)
Inverness CT 0
Hearts 1 (Aguiar 22)
Kilmarnock 2 (Hamill 45p, Fernandez 61)
Dundee United 0
Rangers 2 (Boyd 5, Davis 10)
St Mirren 1 (Miranda 81)