With fewer pool games this season, the margin for error is even smaller for Europe’s elite clubs and so Cullen is keen for Leinster to start with a victory at Montpellier on Saturday.

“The fact that there are only four pool games this year, that becomes even more of a challenge,” Cullen explained.

“We’ve experienced that in the past where, if you lose your first game, it becomes a real challenge to try and get out of your pool.”

Leinster have a rich history in the Heineken Champions Cup, winning the competition on four occasions, with their last success coming as recently as 2018, and Cullen is eager for the PRO14 champions to land a record-breaking fifth title this season.

“We’ve been lucky enough to have plenty of good days, but we’ve also had some very grim ones as well along the way,” he said.

“But it means a huge amount to test yourself against the best teams and individual players all across Europe.

“We come from a system where we’ve got primarily homegrown players representing the club, but we know we come up against lots of global stars from other teams.”

Leinster beat Montpellier twice in the pool stage of the 2018 Heineken Champions Cup on their way to lifting the trophy, but Cullen is wary of the threat the French side pose.

“We’ve played against the Montpellier team in recent seasons, so we understand some of the power that they have, particularly in the forwards, and some of the quality they have in their backs as well,” he said.

“We know that they’re one of the most heavily-backed teams in Europe. They’ve quality right throughout their squad, even to the point where in the Ireland-France game in Paris, the last Six Nations game, Montpellier had five guys starting for France.”

Leinster head coach Leo Cullen believes there will be even more emphasis on their opening game in the Heineken Champions Cup than usual given the new tournament format for this campaign.