NEW YORK: World No. 1 Jannik Sinner recently announced on Friday that he had fired his coach, Umberto Ferrara, and physiotherapist, Giacomo Naldi, after escaping a possible doping ban despite failing two drug tests in March. The Italian tennis player tested positive for the steroid clostebol, commonly used to enhance muscle mass, after Naldi had applied an over-the-counter spray containing the substance to a cut on his hand. Naldi then confronted Sinner, unknowingly infecting him with the essence. The spray was originally given to Naldi by Ferrara. Last week, a court cleared Sinner of any fault or negligence, accepting his