Leinster made light of the absence of Johnny Sexton with a winning start to their European Champions Cup campaign, beating Montpellier 24-17 at the RDS Arena. Sexton has a leg injury but Leo Cullen’s side were 12-7 ahead at half-time thanks to tries from Joey Carbery and Josh van der Flier. Nemani Nadolo, the visitors’ winger, kept them in contention by crossing the line twice but scores from Robbie Henshaw – the man of the match – and Barry Daly sealed a bonus-point victory for Leinster.

The home side were reduced to 14 men for the final six minutes when winger Adam Byrne was sent to the sin-bin yet they managed to hold out.

Pleased to pocket five points in a tough Pool 3, which also contains Exeter and Glasgow, Cullen said: “I feel very relieved. Exhausted. It was pretty stressful watching at times but we’re reasonably pleased with the outcome. It wasn’t pretty at times, but we knew it was going to be a huge challenge.

“For a lot of young guys to step in today, I thought they showed a lot of bravery and courage against some very big, physical individuals. We got a win and we can move on now.”

Leinster were missing Jamie Heaslip, Rob Kearney, Sean O’Brien, Garry Ringrose, Scott Fardy and Sexton, while their captain, Isa Nacewa, also hobbled off during the first half, leaving Rhys Ruddock, Devin Toner and Henshaw to play key leadership roles. The 22-year-old fly-half Ross Byrne was one of a number of young players to step up, with the lock James Ryan and the winger Daly making their Champions Cup debuts, and Cullen expects them to benefit from the experience. “It’s a huge step up for those guys. Guys are coming in for their first games here in Europe, so they’re only going to get better for that experience.”

The Montpellier forwards coach, Nathan Hines, filled in for Vern Cotter, because the head coach was unable to travel for personal reasons. Though a try in each half from Nadolo, coupled with Ruan Pienaar’s seven-point haul, earned Montpellier a losing bonus point, Hines said: “We didn’t play the way we planned. We’re a bit disappointed with our structure of play and every time we tried to apply pressure, we turned over the ball, or a little bit of indiscipline cost us.”

In the Challenge Cup, the Russian minnows Krasny Yar pulled off one of the biggest shocks in club rugby by beating Stade Français, the holders, 34-29. Krasny Yar, founded in 1969 and making their debut in European competition, stunned their illustrious Pool 4 rivals in the Siberian city of Krasnoyarsk as the former Wasps flanker Viktor Gresev scored two of their five tries.

Stade Français, who beat Gloucester in last season’s final at Murrayfield in May, led 12-5 in the first half but Krasny Yar hit back to lead 24-17 at the interval and held on for a famous victory.

Also in Pool 4, Richard Cockerill’s Edinburgh secured an impressive 37-14 win against London Irish at the Madejski Stadium with two first-half tries from the centre Solomoni Rasolea putting them in control.

In Pool 1, Newcastle beat Newport Gwent Dragons 32-27 in a thriller at Kingston Park, where a late converted try from back row Mark Wilson and Toby Flood’s penalty edged the home side to victory.

Worcester registered their first win since April in all competitions after overcoming the early loss of the England centre Ben Te’o to beat Brive 30-20 at Sixways Stadium in their opening Pool 5 match.