Jim Mallinder admits Saints simply haven’t been good enough in Europe this season.
And he is desperate to see his side set the record straight in today’s clash with Castres at Franklin’s Gardens (kick-off 1pm).
Saints were smashed 41-7 by the French team at Stade Pierre Antoine back in October.
And two huge defeats to Leinster were to follow, with Mallinder’s men beaten 37-10 at Franklin’s Gardens and 60-13 in Dublin.
Saints had started their Pool 4 campaign with a gritty 16-14 win against Montpellier, but it all unravelled after that.
And Mallinder said: “We’re really disappointed.
“It’s hard work to qualify and we found that last season. We really battled hard and had some brilliant wins, at Glasgow and Scarlets, to get through to the quarter-finals.
“This year, we just haven’t been good enough.
“We have come up against good sides, but we’re one too and the aspiration and where we want to be is competing at the top end of Europe.”
Saints have bounced back from that double Leinster drubbing by winning three successive Aviva Premiership matches.
And Mallinder said: “We want to keep the momentum going from the last few weeks and we’re still in a big European competition, which this year we haven’t done ourselves justice in.
“We had a good, hard-fought win in the first round against a very good Montpellier side so we were pleased with that, but since then we’ve let ourselves down.
“We want to play well in this tournament on Saturday.”
Saints were particularly disappointed with the defeat in the game at Castres, as a strong side failed to perform and was put to the sword.
“That was a massive disappointment for us because on the back of a hard-working win here we went down there and they really punished us,” Mallinder said.
“We were on the back foot, we were too loose, we turned over the ball too easily and they really capitalised on those chances.”