Scott Murray has warned the rest of Castres Olympique's Pool 1 rivals that the French side are not back in the tournament to make up the numbers.
Having helped his side pick up a bonus point at Franklyn's Gardens in an 18-14 defeat to Northampton saints, the veteran Scottish lock believes the Top 14 outfit can make life difficult to Cardiff Blues when they travel to France next week.
"We let ourselves down with the last pass and our final execution. It was a game we could have won and we did what our coach asked us to do and go out and play with some passion," said Murray.
"We haven't won away from home for a long time, but I think we showed that we are really up for this tournament. French teams are often criticised for not travelling too well, but we got stuck in and could have won in the end.
"The Top 14 is obviously very important to us, but we want to show what we can do in Europe as well. We've got a step up next week with Cardiff Blues coming to Stade Pierre Antoine and the coach told us to have a few beers together tonight and then get ready for the next one."
The Blues, who won the Amlin Challenge Cup in France last season, launch their campaign against one of Murray's former clubs, Edinburgh, in the Welsh capital this afternoon.
