Glasgow - Rangers were boosted by a late winner from the son of Romanian legend Gheorghe Hagi, but Celtic remain on course for a ninth successive title after crushing Motherwell 4-0 on Wednesday.
In-form Celtic striker Odsonne Edouard scored after nine minutes at Fir Park and Leigh Griffiths prodded in number two in the 51st minute.
Callum McGregor added a third with a thunderous volley, then Edouard curled in a wonderful free-kick, his second set-piece goal in two matches, for his 24th goal of the season.
It was Celtic's sixth consecutive victory since they lost to Old Firm rivals Rangers at the end of last year.
The Hoops remain seven points ahead of Rangers at the top of the table, albeit Steven Gerrard's men have a game in hand.
"The quality of our play and the motivation, hunger and desire and quality of the goals was spectacular," Celtic manager Neil Lennon said.
"Odsonne's just special. When he's on that form he's a joy to watch. It was a great finish for the first goal. His link-up play with Leigh was very creative and good to watch."
Ianis Hagi, 21, showed some of his legendary father's quality to keep Rangers in the hunt as his first goal for Gerrard's side sealed a 2-1 win over Hibernian at Ibrox.
Paul Hanlon fired Hibernian in front midway through the first half.
But George Edmundson - back in the starting line-up for the first time since October - slammed home his first goal since joining from Oldham in the summer to level just before half-time.
Rangers, who had dropped five points in their first four games after the winter break, completed their comeback with just six minutes left.
On-loan Genk star Hagi opened his Rangers account with a superb finish from Scott Arfield's header.
"Ianis is a top talent. I said that when he arrived," Gerrard said.
"I thought his performance grew as the game wore on. In the first half he was getting used to the game in Scotland, people knocking him about.
"But he's a brave player. Even if he makes a mistake, he won't shy away.
"His second-half performance deserved to win the match. It's his dad's birthday as well so it's a nice moment for him."
Hearts' home woes against Kilmarnock continued as Daniel Stendel's men suffered a 3-2 defeat.
Goals from Stuart Findlay, Chris Burke and Eamonn Brophy secured a fourth successive victory at Tynecastle for the Ayrshire outfit.
Killie ended the game with 10 men following the dismissal of goalkeeper Laurentiu Branescu and endured a nervous finish following goals from Sean Clare and Craig Halkett.
An early goal from Ali McCann gave St Johnstone a 1-0 win at Aberdeen, who have now gone four league games without a goal.
Ross County registered a first win since mid-December after Billy McKay's double downed Livingston 2-0, while relegation rivals St Mirren and Hamilton shared a 1-1 draw.