Edinburgh led for most of the match, and appeared superior in several facets of the game, but in the end they were let down by indiscipline, and simple mistakes.
Despite losing their first lineout, the visitors then ran in eight points in the first eight minutes. Under pressure in the first scrum of the game, the Lyon pack conceded a penalty and lively Edinburgh scrum-half Sam Hidalgo-Clyne opened the scoring with a goal from 38 metres out.
Five minutes later, Edinburgh capitalised on a poor clearance kick from Lyon, first running the ball back and breaching the defence in midfield, before some slick passing put Scotland winger Tim Visser over for a try in the corner.
Trailing 8-0, Lyon finally got going and started to hold on to the ball rather than kicking it aimlessly away Edinburgh were on the back foot but managed to repulse a dangerous rolling maul near their goal-line Kiwi stand-off Lachie Munro eventually opened Lyon’s account with a penalty goal from 41 metres.
The home side again looked dangerous, with their captain, former French international Fabrice Estebanez, sparking a counter-attack from his own 22. Edinburgh once again found themselves defending a lineout five metres out but, once again, the superior organisation of the Scottish pack kept their line intact.
Almost against the run of play, after 25 minutes Edinburgh struck again with a try by their other winger, Dougie Fife. Superb counter-rucking by Dave Denton created a turnover near half-way, Jack Cuthbert angled a kick into the corner, and Fife won the race to touch down near the corner post.
Edinburgh were now ten points ahead at 13-3 but, after repeatedly flirting with the offside law in the ruck, the Scots paid the price in the 30th minute, with Matt Scott yellow carded for repeated infringing.
Lyon immediately upped their intensity, desperate to close the gap before half-time. Edinburgh’s defence rose to the challenge however and, despite another handy attacking lineout close to the visitors’ line, Lyon’s attempted rolling maul failed to gain any ground.
Two minutes before the break, however, with Scott still in the sin-bin, Lyon finally managed to drive home their advantage. After a ferocious sequence of play in the Edinburgh 22, the inevitable happened, Munro saw an overlap out wide, fired a long miss pass to Romain Loursac on the left flank, and the fullback crashed over in the corner.
Munro converted from the touchline, and, at half-time, Lyon were back in the game, at just 13-10 down.
After the break, Hidalgo-Clyne once again gave his team some breathing space with a second penalty goal but, despite having rested many of their senior players, the Lyonnais continued to apply the pressure.
Inside his own half, Fijian No.8 Masi Matadigo threw a quick lineout ball to Loursac in centre field, who kicked a well-judged up-and-under. His opposite number Cuthbert fumbled the catch, a Lyon boot kicked ahead, and Aussie hooker Damien Fitzpatrick dived on the ball to score his side’s second try.
Munro missed the conversion from out in front, but Edinburgh still held on to a slender lead at 16-15.
Lyon finally snatched the lead in the 65th minute when replacement full-back Jérôme Porical kicked a penalty from 45 metres out to make the score 18-16 in his side’s favour.
Soon after, Hidalgo-Clyne was again on target for Edinburgh but, with only four minutes to play, Lyon had a long sequence of play in the Edinburgh 22 before captain Estebanez calmly kicked the winning drop goal.
The losing bonus point, though, leaves Edinburgh on top of Pool 4, a point ahead of Bordeaux-Bègles.