Stade Français centre Felipe Contepomi kicked six penalties to help his team to an opening 23-14 Amlin Challenge Cup win over Worcester at Sixways on Thursday.
The hosts outscored their French visitors two tries to one, however Contepomi's boot and the Warriors ill-discipline ultimately proved to be the difference between the two sides in this Pool 1 clash.
The Pumas skipper led the way as Stade Français stormed back from 14-0 down to claim a superb come-from-behind victory.
Worcester put themselves in the driving seat early on thanks to tries from captain Chris Pennell and Marcel Garvey, converted by Joe Carlisle, in the opening 12 minutes.
But Contepomi's contribution of 18 points from the tee and a try from former England winger Paul Sackey put the game beyond the Warriors who, after such a brilliant start, failed to even claim a losing bonus point.
Meanwhile, Toulon opened their Amlin Challenge Cup account with a 53-22 victory over a spirited Petrarca outfit.
After leading the Italians by just five points at half-time (22-17), Toulon produced a clinical second-half performance - scoring four tries - to put the result beyond doubt.
Petrarca took a surprise 6-0 lead early on thanks to two penalties from Irishman Eoghan Hickey, but the hosts then took control scoring three tries in the space of eight minutes through prop Levan Chilachava, Baptiste Bonnet and Romain Frou - Toulon pivot fly-half Julien Dumora adding two conversions.
Hickey then narrowed the deficit with his third shot at goal before lock Agustin Cavalieri touched down for the Italians' first try. Hickey missed the conversion but added another penalty three minutes later.
Toulon had the last say of the first forty minutes when Dumora slotted over a penalty on the stroke of half-time.
After the break, Toulon began the second period in style. First Christian Loamanu touched down, followed by Benjamin Lapeyre to give the French side a healthy 34-17 lead.
A penalty try and a score from Xavier Chiocci kept the scoreboard ticking over for the 2010 Amlin Challenge Cup finalists before Scott Palmer grabbed one back for Petrarca.
Alafoti Faosiliva rounded off the scoring, touching down six minutes from time to take Toulon through the fifty point barrier.