It looked as if Castres would progress from Pool B as they led Harlequins 33-29 going into stoppage time at Twickenham Stoop in Round 4 on Friday and were set for a bonus-point victory.

However, those five points became just two as Quins edged home 36-33, thanks to Alex Dombrandt’s try and Marcus Smith’s conversion, which left Castres 11th in the pool rather than seventh and so relegated to the EPCR Challenge Cup.

“We’re obviously gutted,” Worsley told BT Sport. “The team put in a really good performance tonight.

“A few decisions didn’t go our way at the end, but we have got to hold our hands up as well. We made a lot of errors in the game and lost field position because of those errors.

“They scored a few tries out of the back of it and we also missed kicks. At the end of the day, it was those that made the difference.”

This latest reverse meant Castres suffered four narrow defeats in their four pool matches, finishing with a points difference of just –14 and five bonus points.

While this exit will hurt for some time, Worsley could at least point to the strength in depth Castres’ Heineken Champions Cup campaign had illustrated.

He said: “A number of guys haven’t played that much rugby until the European Cup and some of them really put their hands up. There were a few guys who played outstandingly well tonight.

“We are glad about that, but we are also just gutted at the moment not to be continuing in this tournament.”

Castres Olympique defence coach Joe Worsley rued his side’s mistakes as they suffered an agonising exit from the Heineken Champions Cup at the weekend.