Rangers opened up a four-point gap over Celtic at the top of the Scottish Premiership thanks to a 2-0 victory in the Old Firm game on Saturday.
Connor Goldson scored in each half to earn an important victory at Celtic Park.
He headed in from James Tavernier's free kick in the ninth minute to give Steven Gerrard's side an early lead.
Rangers captain Tavernier had a major influence on the game and went close himself soon after the goal.
Celtic had a good chance to equalise on 14 minutes but Mohamed Elyounoussi shot over when through on goal.
Despite being played behind closed doors the game was not without controversy. Rangers striker Alfredo Morelos got away with an off-the-ball whack on Celtic captain Scott Brown on 38 minutes.
Goldson doubled Rangers' advantage on 54 minutes, the defender turning in Scott Arfield's cross from the right wing.
Celtic, who were without several players due to COVID-19 as well as James Forrest due to injury, can reduce Rangers' lead to a single point if they win their game in hand.