Shane Berne goes for a Leinster try against the Ospreys
Leinster extended their lead at the top at the Magners League as they came from behind to defeat the Ospreys 16-10.
Even without some of their big name Irish internationals, Leinster struggled to match the Ospreys - playing their third game in six days - in the first half.
And despite turning it round after the break, coach Michael Cheika was far from satisfied with the performance from his troops.
"I didn't have to say too much to the boys after the game," he said. "In the first half we were average at best.
"The Ospreys are a very good side and we know that we were probably lucky to be only six points behind at the break.
"They played with a big hard defence (against us) and I'd say that we could see them (the Ospreys) again before the end of the season with the way things are shaping up.
"We rested a couple of players tonight and could have a few more players to maybe come back next week. We'll just wait and see."
The Welsh region impressed in the opening 40 minutes with outside-half Dan Biggar converting his own try and kicking three penalties as Leinster looked destined for a first home Magners League defeat since September 2008.
But, playing their third game in six days, the Ospreys began to tire and tries from Shaun Berne and Isa Nacewa turned round the game in the second period.
Italy Under-20s held off a late Samoa blitz to retain their place in the World Rugby U20 Championship on Saturday and head coach Alessandro Troncon believes the experience will have served as a valuable lesson for his young troops.