Last season's finalists Scarlets travelled to Wales to face Connacht.
Edinburgh travelled to Leinster in a bid to build on Round 3's victory over Connacht.
After a succession of narrow defeats, could Cardiff Blues pick up their first win of the season vs Munster?
With three straight wins, Ulster travelled to Bloemfontein aiming to make it four against the winless Toyota Cheetahs.
Dragons welcomed Zebre to Rodney parade in hope that they could add a second win to the tally this season.