He praised his side’s resilience after consigning Castres to a first home European defeat since 2015 and a first loss against any opponents at Stade Pierre Fabre in 2021. Quins had also been the last visitors to record a European win there.

“It was tough,” Matson told BT Sport. “I think their record shows how hard it is to come here and get a victory. It was close right to the end, so I’m very proud.”

Matson admitted his side were never comfortable, but credited Castres for that.

He said: “We tried to shift them around. We thought that if we could play with a bit of tempo, we could eventually get some tries. But they defended really well and put us under pressure defensively, and we made some errors, which kept them in the game and kept it close right to the last minute.”

Next up for Quins in Pool B is Cardiff Rugby at home in Round 2 on Saturday.

Matson said: “The great thing about the Heineken Cup is playing completely different teams from different countries and Cardiff will be a completely different animal. But we are at home, so we are really looking forward to that game.”

Harlequins head coach Tabai Matson had no doubts that the English club had gained a major scalp in their 20-18 Heineken Champions Cup victory at Castres Olympique in Round 1.