It was Mas' first appearance since the World Cup final on October 23 when France were edged out 8-7 by New Zealand in Auckland.
And Mas admitted it was great to be able to help his side get their season back on track and put the World Cup disappointment behind him.
He said: "We had been affected by all the lost games at home, and it was really in our heads. The guys refused to give up and that's a good thing. The squad want to enjoy themselves. But it wasn't easy against a well-organised Exeter side and in those circumstances it's not easy.
"We showed a lot of willingness and that's how we are going to improve."
Elsewhere Mas' French teammate Alexis Palisson made his first appearance for Toulon after his summer move from Brive.
The winger played an hour of the comprehensive 53-22 win over Petrarca Padova as he looks to impress new France boss Philippe Saint-André ahead of the 2012 RBS 6 Nations.
Finally former England winger Paul Sackey scored the only try for Stade Français in a 23-14 win over Worcester in Paris.