Leinster beat defending Pro14 champions the Scarlets 20-13 to go top of Conference B, while there were also wins for the Cardiff Blues, Edinburgh, Ospreys, Glasgow Warriors and Zebre.
The Scarlets went ahead with an early try from wing Johnny McNicholl, which was converted by flyhalf Dan Jones.
However, Leinster took a 10-7 lead into half-time, thanks to two unconverted tries from wing James Lowe.
Leinster extended their lead in the second half with a converted try from scrumhalf Luke McGrath, before replacement centre Ciaran Frawley kicked two penalties to give the home side a 20-13 win.
In other results, the Kings let a five-point half-time lead slip to lose 26-12 to the Ospreys, the Glasgow Warriors scored five tries to beat the Cheetahs 37-23, Cardiff saw off Munster with a 25-18 win, Edinburgh flyhalf Duncan Weir kicked a last-minute drop goal to earn a 17-16 win against Ulster, while Zebre ended Connacht’s three-match unbeaten run with a 19-11 victory.
Round 15 results:
Leinster 20 Scarlets 13
Ospreys 26 Kings 12
Glasgow Warriors 37 Cheetahs 23
Cardiff Blues 25 Munster 18
Ulster 16 Edinburgh 17
Connacht 11 Zebre 19
Photo: Seb Daly/Sportsfile