Porical, who kicked 20 points in all, watched with delight when his 78th-minute penalty fell the right side of the posts after twice hitting the woodwork.
The Perpignan-born fullback had pulled his side level four minutes earlier by kicking a long-range penalty from 60 metres.
The home team had gone in front early thanks to tries from Guilhem Guirado and James Hook but could not secure a big enough lead.
Stade Francais, who have failed to qualify for the French Top 14 final stages and are banking on the Amlin Cup to book a place in next year's Heineken Cup, face champions Biarritz or Irish side Leinster in the final of Europe's second-tier competition in Dublin on May 17.
- Sports & Recreation
- Heineken Cup
- Guilhem Guirado