Lyon scored 17 unanswered points in the final 15 minutes to come from behind and defeat Sale Sharks 27-24 in Friday's scintillating Challenge Cup clash.
It was the second nail-biting encounter in as many outings for Sale in this competition, following their 20-20 draw with Toulouse last week, although this time they were left with just a losing bonus point to console themselves.
Sale led 24-10 with a quarter of an hour remaining but the hosts ran in two tries, Frederic Michalak converting both before slotting the decisive penalty as Lyon responded smartly from their loss to Cardiff Blues on matchday one.
Lyon dominated the first period but trailed 14-10 at the break despite Sale spending just seven seconds in their opponents' 22 thanks to Denny Solomona's interception try and Sam James' breakaway score.
The home side hit back before half-time through Delon Armitage, but another interception saw James cross for his second in the 56th minute.
Liam Gill went over under the posts to bring the Top 14 leaders back to within seven, Theo Belan's try levelling matters in controversial fashion with Sale claiming Lyon jumped into a tackle in the build-up, before Michalak kept his cool from the tee as Sale were pinged for offside.
The other match in Pool 2 saw Cardiff edge another tight clash, prevailing 17-15 at Toulouse thanks to Macauley Cook's try early in the second period.
Cardiff top the table with nine points from two matches, with Lyon on four and Toulouse and Sale locked on three apiece.
In Pool 5, Brive romped to a 38-13 win over fellow Top 14 strugglers Oyonnax, Gaetan Germain scoring one of his side's five tries to finish up with 16 points.