Cardiff got their campaign up and running with a bonus-point victory over Top 14 leaders Lyon, the Welsh outfit emerging 29-19 victors at Cardiff Arms Park.
After waiting 22 minutes to break the deadlock, the Blues fashioned converted tries from George Earle and Tomos Williams to earn a 14-0 half-time lead.
Macauley Cook's try stretched Cardiff's lead further before Lyon took advantage of Kristian Dacey's 58th-minute yellow card to open their account through Virgile Bruni's score.
However, Cardiff nipped any Lyon fightback in the bud when Rey Lee-Lo crossed for their fourth try, putting the hosts 26-7 ahead and earning them a bonus point.
Lyon grabbed two tries towards the end through Pierre-Louis Barassi and Jone Tuva - the second when down to 13 men - but it was too little too late.