Glasgow Warriors are the only club to have won each of their opening three fixtures after overcoming the Cheetahs.
Saracens needed two late tries from David Strettle to secure a come-from-behind victory over Northampton Saints.
Argentina's resolve was key to the surprise win against Australia, says head coach Mario Ledesma.
Television footage showed Lukhan Tui arguing with a supporter following Australia's Rugby Championship loss to Argentina.
David Pocock was left frustrated by Australia's wastefulness as they were beaten by Argentina in the Rugby Championship.
Frustrations boiled over after Australia's loss to Argentina, with Lukhan Tui involved in an altercation with a fan.
Australia's dismal Rugby Championship continued with a rare home loss to Argentina on the Gold Coast.
Rassie Erasmus says South Africa's win over New Zealand is the best moment of his coaching career, but insisted the Springboks must improve.
New Zealand missed the chance to wrap up the Rugby Championship as South Africa earned a famous win in a Wellington thriller.
New Zealand coach Steve Hansen would not blame referee Nigel Owens or fly-half Beauden Barrett for the loss to South Africa.