The standout team in Pro14 could only manage a 3-0 win against winless Zebre as Leinster struggled on Saturday.
Friday's Pro14 fixtures saw a trio of easy victories as the Cheetahs, Leinster and Connacht all won by big margins.
Ulster suffered a hammering in Bloemfontein, where wing Anthony Volmink scored three of nine tries for the Cheetahs.
Dave Kearney's hat-trick helped Leinster begin the defence of their Pro14 title with a win over Benetton Treviso.
Munster, Racing 92 and the Ospreys will take on holders Saracens in the pool stage of the 2019-20 European Champions Cup.
Glasgow Warriors celebrated the news that head coach Dave Rennie will stay at the club by securing a famous win over Leinster in Dublin.
Iliesa Ratuva Tavuyara touched down and Tommaso Allan converted with the last play of the game as Benetton Treviso held Leinster in Dublin.
Connacht were blown away in the first half as Sale Sharks booked their place in the European Challenge Cup semi-finals.
Cardiff Blues used Wales Grand Slam heroes Gareth Anscombe and Josh Navidi from the start in their demolition of the Scarlets.
Wales international Leigh Halfpenny featured in the Scarlets' 10-6 win over Munster, while Glasgow Warriors went top of Conference A.
Glasgow Warriors closed the gap on Munster at the top of Conference A, despite both recording wins in the latest round of Pro14 fixtures.
Nico Lee apologised for clearing the contents of his nose onto an opponent, which will see him banned until July 21.
Zebre put on a spirited showing but ultimately fell short against Pro14 heavyweights Leinster.
Southern Kings produced a stunning late fightback to claim only their second win of the season, halting Edinburgh's impressive run.
For the second time in two days, a side racked up a century of points in the Challenge Cup as Bristol Bears routed Enisei...
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Ryan Mills' last-gasp drop goal put Worcester Warriors into the last eight of the Challenge Cup for the first time in a decade.