The Ospreys were poor against the Irish province, but they are determined to produce their best when it really matters - in Europe.
"This is the main competition away from international rugby, so we will not need any motivating going back into it," said Phillips.
"It's a massive game - a must-win, with so much riding on it.
"We are all aware of what's at stake and we realise how difficult it will be, but we are looking forward to the challenge.
"We were frustrated by our display against Munster and didn't play as we can. We know we are a better side than we showed.
"But now we have to take our anger out on Perpignan. What we have to do is play as well as we can.
"If we can do that, we'll have a chance."