Deylaud, dropped by France during the Five Nations tournament but back in the World Cup squad, kicked seven penalties, a conversion and a drop goal to seal the 31-16 win for the reigning champions over Castres.
An early drop goal from Francis Rui and an exchange of penalties saw Castres go 6-3 ahead before their scrum-half Frederic Seguier touched down in the left corner.
The Castres lock Guy Jeannard and the Toulouse full-back Stephane Ougier were then sent off for 10 minutes for fighting.
Toulouse reached half-time 16-6 down but Deylaud slotted three more penalties within 15 minutes and by the 57th his sixth put Toulouse ahead at 18-16.
There was just time for a pushover scrum, with full-back Ougier scoring, and a Deylaud conversion and drop goal.