Northampton overcame the loss of injured captain George Furbank to post a statement 30-21 Investec Champions Cup win against the Bulls in Pretoria.
A round-up of Saturday's Investec Champions Cup action, where Northampton and Saracens made winning starts but Exeter were beaten by Sharks in South Africa.
Defending champions Northampton suffered a shock defeat to Gloucester, while Bath returned to top of the Premiership and Sale beat Leicester.
Bristol regained top spot in the Gallagher Premiership as centre Kalaveti Ravouvou scored two tries to underpin a 31-23 victory over champions Northampton at Ashton Gate.
Northampton bounced back from their derby disappointment in style as they trounced Sale while Newcastle earned their first Premiership victory in over a year.
Leicester made it three wins from four under Michael Cheika as they beat rivals and defending champions Northampton 24-8 on Saturday.
England wing Tom Roebuck scored two tries as Sale secured a breathless 31-27 bonus-point win over Gloucester in the Gallagher Premiership.
Leigh Halfpenny celebrated a first Gallagher Premiership try as Harlequins picked up a 28-14 bonus-point victory over Newcastle at Twickenham Stoop.