Cousin had been expected to leave Ibrox this summer and Smith admitted he could still leave before the transfer window closes on Monday night but that there was no current interest.
"There is nobody in for him at the present moment, so he is staying here and we'll continue to use our strikers," Smith told BBC Radio Scotland.
"He has been inconsistent since he came here but as he showed today he has that capability. He is excellent when he's on form like today."
Smith felt the sending off was harsh after Cousin was twice booked for leading with his arm in aerial challenges.
"It used to be a feature of play in the game, a battle between the centre-forward and centre-half," he said.
"Yes, they were fouls but there was no malice between Daniel and Gary Caldwell.
"It was two players committed to winning the ball. It's a shame it ends up with a decision like that."
Smith was pleased with the football his side played and with Pedro Mendes, who scored a brilliant 25-yard strike on his Old Firm debut.
"He has brought a bit of football to us," Smith said.
"He is certainly making a difference in the way we play football overall."