The Scarlets gave three-time Champions Cup winners Toulon an almighty fright before finally being edged out 21-20 in their Pool Five encounter in France.
The Welsh side bounced back from letting the home side take an 18-point lead as they forced their noses in front in the second half before finally coming up just short.
Toulon scored at a point a minute in the opening quarter of an hour as they punished last season's Guinness PRO12 champions. They scored two tries and looked in complete control of their opening game of the tournament.
Scrum-half Eric Escande intercepted a pass by opposite number Aled Davies from a line-out near halfway to scamper 40 metres to the line, and then skipper Guilhem Guirado rounded off a thrilling break from the 22 with a try in the corner.
Outside-half Anthony Belleau converted Escande's try and also kicked two penalties to leave the Scarlets trailing by 18 points.
But they were eventually able to get some possession and got points on the board before the break when Leigh Halfpenny kicked a penalty against his former club.
Home full-back Hugo Bonneval was sent to the sin-bin for taking out Davies at the breakdown and Scarlets almost scored at the end of the first half with a one-man advantage - Johnny McNicholl reached the line after a sweeping move from right to left, but lost the ball in the act of scoring.
Scarlets made their extra man count at the start of the second half when McNicholl leaped above Chris Ashton to pick off a crossfield kick from Rhys Patchell to bag a try that Halfpenny converted.
Things got even better eight minutes later when the Scarlets and Lions full-back knifed through for a try that he converted to make it a one-point game.
Now it was the visitors who were in the ascendancy and when Halfpenny stepped up to kick a penalty on the hour it was the Welsh side who were ahead after scoring 20 unanswered points.
The lead did not last long as four minutes later Tadhg Beirne was penalised at the breakdown and Francois Trinh-Duc regained the lead for his side with a 30-metre penalty.
The drama did not end there as Halfpenny kicked a difficult penalty wide of the mark and Toulon's Sebastien Tillous-Borde was held up over the line in the 81st minute.
