Vern Cotter’s men ran riot to rout a Toulouse side that had won three and drawn one of their first four games, scoring 10 tries in a devastating display.
Last year’s runners-up showed no mercy after the break. Nadolo and Fall touched down again and Picamoles added another three, with Pienaar scoring 10 points from the tee and Johan Goosen slotting the extras on three occasions.
Two Arthur Bonneval tries were no consolation for 14-man Toulouse as they were put to the sword.
Watisoni Votu’s second-half double gave Pau hope, but they gave themselves too much to do.
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