Alain Rolland has never been afraid to make the big calls on the rugby field, and when the Irish referee sent two Leicester players to the sin-bin at the same time in the second half, it signaled the end of the visitors' hopes of picking up any points at all in this vital pool four showdown.
The man who sent off Wales captain and flanker Sam Warburton for a dangerous tackle after only 19 minutes of the World Cup semi-final, this time dispatched Tigers hooker George Chuter and England centre Manu Tuilagi for two separate incidents in the same sequence of play after 49 minutes. The first card, on the recommendation of his touch judge, went to Chuter for his high and late challenge on Morgan Parra; the second went to Tuilagi for a clumsy, head-high tackle on prop Vincent Debatty.
The packed crowd of 18,000 were baying for blood when both Parra and Debatty were floored and they roared their approval when the yellow cards were flashed. Their pleasure was then doubled when less than three minutes later the man of the match, Wesley Fofana, stretched out to score the first of his two tries to increase the lead to an impressive 23-5.
There was only ever going to be one result after that try, and Fofana's second score increased the home advantage to 25 points after 66 minutes. A bonus point looked highly likely at that stage but, to Leicester's huge credit, they used their scrum dominance to conjure up a penalty try seconds after Julien Bonnaire had become the third player to be sent to the sin-bin, and they held their line bravely for those final 14 minutes.
It means there is still all to play for in the return leg in Leicester this weekend. Clermont have moved to the top of the pool on 10 points, Ulster, who picked up a try bonus in their big home win over Aironi, and will be chasing another five in Italy in round four, are second on nine, while the Tigers are one behind on eight.
"We are still in there and we denied them a bonus point. So there is still plenty to play for at Welford Road," said Richard Cockerill, the Leicester director of rugby. "The best side won on the day. The yellow cards didn't help of course, but we will lick our wounds and we will get up for the return game next week.
"The atmosphere in Clermont is pretty volatile, and everyone lies down as if they have been shot, but Alain is a good referee and he dealt with it as he saw fit," Cockerill added.
While there was plenty for Cockerill to be pleased about in his side's performance – the scrum and line-out in particular proved very effective – the dropped high ball by their powerhouse wing, Alesana Tuilagi, in his 22, three minutes before the break, was almost as bad a moment as the double sin-binning. Julien Malzieu profited with the home side's first try and a 9-5 lead turned into an 11-point gap at a crucial stage.
The Tigers will know all too well that a win next week at Welford Road is imperative, or their European adventure will be more or less over for another year.
Scorers : Clermont - Tries: Malzieu, Fofana (2); Conversions:: Parra (3); Penalties: Parra (3) .Leicester - Tries: Youngs, penalty try; Conversion: Flood.
Clermont Auvergne:: L Byrne; S Sivivatu, A Rougerie (capt, R King, 78), W Fofana, J Malzieu; B James (D Skrela, 75), M Parra; V Debaty (D Kotze, 69), B Kayser (T Paulo 48), D Zirakashvili (C Ric, 37), J Pierre (J Cudmore 72), N Hines (E Vermeulen, 76), G Vosloo, A Lapandry, J Bonnaire.
Leicester Tigers: G Murphy (capt); H Agulla (S Hamilton, 72), M Smith (B Twelvetrees, 72), M Tuilagi, A Tuilagi; T Flood, B Youngs; M Ayerza (B Stankovich, 52), G Chuter (R Hawkins, 60), M Castrogiovanni (D Cole, 61), L Deacon (E Slater, 75), G Skivington, T Croft, J Salvi, S Mafi (Hawkins, 56-60, T Waldrom 60) .
Referee: A Rolland (Ireland).