Leinster were awarded the first penalty of the match after just a couple of minutes, with the Ospreys defence caught offside after a decent run from Leinster winger Jordan Larmour and a flanker Ross Moloney. But it was the outside half Ross Byrne that claimed the first points through the boot, converting the penalty into three points.
A second, more questionable penalty was awarded just ahead of the ten-minute mark and allowed Leinster a platform from Ospreys’ 5m line. However, the visitors in white held fast and kept Leinster out for a long five-minute period of sustained pressure before a penalty allowed Ospreys outside half Stephen Myler to clear the lines.
A knock on from the Ospreys allow Leinster a free shot to run it and a grubber kick through allowed Leinster winger Larmour to pounce on the ball over the try line. The conversion attempt struck the upright which meant Leinster enjoyed a 8-0 lead heading into the final 20 minutes of the first half.
It looked like Leinster had bagged a second moments later, but the ball was knocked on before they regathered it, so play was brought back for a scrum; however, the pressure was still on the Ospreys as they defended on their 5m line. The pressure mounted and it was Ospreys number eight Morgan Morris who bore the wrath of the referee, being shown a yellow card and the visitors would be a man down for most of the remainder of the first half. The sacrifice was futile, as the Leinster pack eventually powered over the whitewash and Cian Healy claimed the spoils, and with the conversion added, Leinster edged further ahead 15-0.
A parting shot from the Ospreys in the dying moments of the half were promising, with captain and scrumhalf Rhys Webb finding a gap around the breakdown and putting a kick through for winger Keelan Giles to chase. The pressure from the speedster caused the retreating Leinster defender to spill the ball forward on their own 5m line, which would have given the Ospreys a fantastic position to attack from. Alas, the clock was in the red and referee Andrew Brace blew his whistle for half-time and both teams retreated to the changing rooms with Leinster still 15 points ahead.