Mourinho dropped the former Newcastle winger for the game, with the Frenchman taking to social media pre-match to hit out at his omission
He posted: "It will take more than this to defeat me.
"When a lie takes the elevator, the truth takes the stairs. It takes longer but it always arrives in the end. If God is with us, who can be against us? Romans 8:31."
The post drew a response from Mourinho, who declared: "I didn't know Saint-Maximin was talented in poetry.
"I'm not bad in that regard either. When a football player works well, works hard, trains every day, he is fit and can climb the stairs. He doesn't need an elevator.
"However, if a player doesn't train well, arrives late, is overweight, is not ready to play, he needs an elevator to go up. Because he gets tired quickly on the stairs."
Saint-Maximin then chose to react to Mourinho, posting his weight and stating: "Lies produce flowers but not fruit."
Fener won 2-0 at Ibrox last night, but were dumped out on penalties as Rangers reached the Europa League quarterfinals.