Leinster are five points clear at the top of Conference B after the defending champions beat Munster at the Aviva Stadium.
Olly Robinson's late try completed a second-half comeback from Cardiff Blues as they secured a Pro14 victory over the Cheetahs.
The Cheetahs' three-match losing run in Pro14 ended but a last-gasp try saw Ulster deny them victory.
Glasgow Warriors are the only club to have won each of their opening three fixtures after overcoming the Cheetahs.
Pro14 champions Leinster were defeated by last season's runners-up Scarlets in a tense clash on Saturday.
Bryan Byrne's late try and Ross Byrne's subsequent conversion saw champions Leinster snatch victory over Cardiff Blues in the Pro14.
Ireland legend Brian O'Driscoll heaped praise on the retiring Sam Warburton after the former Wales captain announced his retirement.
After announcing his retirement from rugby, Sam Warburton has found the messages of support "overwhelming".
Sam Warburton was expected to return from injury but his retirement on Wednesday made him just the latest star to announce a shock decision.
Sam Warburton's retirement from rugby brought a strong response on social media, with Gareth Bale among those to wish him well.
Following Sam Warburton's shock retirement, we recap his sublime career with Opta statistics.
Sam Warburton announced his shock retirement on Wednesday, prompting Warren Gatland to laud the "outstanding" rugby star.
Wales great Sam Warburton, 29, has retired from rugby after admitting "my body is unable to give me back what I had hoped for".
Cardiff Blues won the European Rugby Challenge Cup for the second time with a 31-30 victory over Gloucester.
Jarrod Evans kicked 11 points as Cardiff Blues defeated Pau 16-10 to reach the final of the European Challenge Cup.
Leinster were unable to seal a home semi-final as Benetton Treviso consigned them to a shock home defeat in the Pro14.