LONDON : Catching a millionaire Grand Slam champion in action on the second-tier Challenger Circuit is a rare sight, especially since cheering fans and creature comforts are in short supply when compared to the glitz and glamour of the main ATP Tour events. Yet this is the world that Marin Cilic, who has amassed a fortune of almost $32 million in prize money alone, has been circulating in for most of this year after his ranking nosedived to outside the Top 1000 following knee surgery in 2023.