Leinster flanker Jordi Murphy only found out 10 minutes before kick off that he would be pitched into the derby with Ulster.
The Ireland back row seized his opportunity and was instrumental as Leinster secured a valuable victory.
Murphy explained: “Just before the game Matt called Josh ( van der Flyer) and myself over and said ‘the General’ (Shane Jennings) looks a doubt and that I was starting and he was on the bench.
“Josh came on and did a really good job for us, he has been playing well for us this season and is now into double figure caps,” added Murphy.
Murphy felt the reason for Leinster’s victory was they won the battle at the breakdown.
“It was one of the focuses of the week as we were beaten there against Connacht, we identified their threats because they have a very good turnover rate and they are hard at the breakdown with boys like Best, Wilson and Diack.”
“We executed the plan well to be more aggressive and to try and get our second man in there quickly and we were happy enough with that aspect, we can still improve but we were happy.
Ian Madigan scored an opportunistic try at the start of the second half and Murphy revealed the Leinster players were just as surprised as Ulster.
“He told us to get ready for the lineout, Devin (Toner) called us all in and the next thing he was over.
“But that is Ian for you he fooled everyone not just them but us as well.
“He was either going to kick or we were going to go for the corner and hope to drive over from the maul.
“They were down a man and we had to put the pressure . We scored and he converted and that put us a bit ahead.
“When you are more than a try ahead and our keeping the pressure on you feel in control but Ulster came back well as they always do but we felt confident in our game plan and we got the try at the end which put a bit of gloss on the score line.”