A late Brian O'Driscoll try inflicted Munster's first defeat of the season and their fifth in a row to Leinster in front of a Magners League record crowd at the Aviva Stadium.
And while Murphy maybe a Magners League newcomer, his Kildare routes ensure he is fully immersed in the traditions of Munster versus Leinster, hence the pain of defeat.
"I have experienced big games but this is as disappointed as I have been in my career," Murphy told the Irish Times.
"It's different. Nobody can tell you about the rivalry or the feeling when you win or lose.
"It's absolutely gutting. A bounce of the ball another way and we could have got a try and probably won the game."
Murphy and Munster now turn their attentions to European competition and a mouth-watering Heineken Cup opener against London Irish on Saturday.
And with four Magners League wins already under their belt, the 2006 and 2008 continental champions have plenty of positives to take to the Madejski Stadium, even if a painful review of the Leinster game is a necessary process early this week.
"Positives? We are going to learn a lot about ourselves when we look back and review our game to see what we need to do against London Irish," added Murphy.
"The next two weeks are massive. If we get two wins we're set up because it is a really tough group."
Those sentiments were echoed by stand-in Munster skipper Denis Leamy who insisted that the Red Army must put the pain of derby defeat behind them in time for the trip to Reading.
"Let's be honest, it hurts an awful lot," said Leamy.
"What do we do? We can't dwell on it. We've had a decent start. We came up here to win the game but that didn't happen. Leinster probably just deserved it.
"We'll take the positives and move on. We have to. We have no other choice.
"There is work to be done but it is not all bad. It is a great game to get under our belts - two of the best teams in Europe, I feel.
"Leinster would probably say they needed the result but we needed it as well. Unfortunately we didn't get it. There is a lot of rugby to be played this season and we'll be back."
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