DaMarcus Beasley, the USA international winger, was also on the mark for Gers, with manager Walter Smith declaring: "I thought DaMarcus Beasley did very well and so did Jean-Claude when he came on.
"We have a choice there that we didn't have last season and that will be a big benefit to us over the season."
Cousin has been rated doubtful for Tuesday night's Champions League qualifier against Red Star Belgrade after picking up a knock against Killie, but Lee McCulloch is available for the trip to Serbia after missing out today through illness.
Smith said: "Cousin took a kick on the calf and has a bit of swelling there so he will be doubtful for Tuesday night's game.
"We will know better within the next 24 hours and after training on Sunday. But he is a doubt as it stands at the present moment.
"I left Lee McCulloch out because he had an illness during the week. He could have played if necessary but I felt it was better with Tuesday night in mind to keep him out. He will be okay for Tuesday."