Prediction and head to head Marin Cilic vs. Christian Garin. There is no head to head record between Marin Cilic and Christian Garin since this will be the first time that they will fight against each other at pro level.. Prediction. The favorite for Tennis Tonic is Marin Cilic that should win in 2 sets.. Betting odds. According to bet365, Marin Cilic is the favorite to win the match.