Leinster defeated Clermont Auvergne 48-23 in the first round of the Champions Cup at the Stade Marcel-Bertrand. The match opened with a minute's silence for Lions prop Hyron Andrews, who died on Friday at the age of 31, the day before his South African club's match in La Rochelle.

Leinster took the lead in the ninth minute when Tadhg Furlong scored, following up on a close call by Jimmy O'Brien. Dan Sheehan added a second try for the visitors after the home side lost possession. Clermont responded with a try from Joris Jurand, while Harry Plummer recorded 11 points, including a long-range penalty that gave the home side a one-point lead at half-time — Clermont led 16-15.

In the second half, Leinster took control. Sam Prendergast scored within two minutes of the restart, and referee Matthew Carley awarded a penalty try as Prop N'Folo N'Golo was sent to the sin-bin for 10 minutes in the 56th minute. Sheehan then scored his second try, with Mathieu Bertholet responding for Clermont. In the final 15 minutes, Jack Conan and Tommy O'Brien rounded off a convincing victory for the visitors. Prendergast finished with 16 points, with three conversions and one penalty, while Plummer scored two conversions and three penalties for Clermont. McCarthy was sent off in the 80th minute.

Leinster were seeking their fifth European title in this match, having lost the final in May after eight seasons. Head coach Leo Cullen included a number of Irish players in the squad. Clermont, in the French Top 14, were in crisis this season with four defeats in six matches.