Wikipedia - Denis Kudla
Denis Kudla ( KOOD-lə; born August 17, 1992) is a tennis coach and a former professional player. He had a career-high ATP singles ranking of world No. 53, achieved in May 2016. He had a career-high doubles ranking of No. 133, achieved in August 2018. He won nine Challenger singles and nine doubles titles in his career.
He is currently coaching Reilly Opelka.