By Matt Hardy On Sunday Jannik Sinner toppled Taylor Fritz in straight sets to win his first US Open and second career Grand Slam. The dominance of the Italian and fellow European Carlos Alcaraz ensured that for the first time since 2002, none of Novak Djokovic, Roger Fedderer or Rafael Nadal won one of the four calendar slam events. But the 23-year-old isn’t new to success this season, and neither is his team. His two coaches – Darren Cahill and Simone Vagnozzi – were controversially both crowned Coach of the Year at the 2023 ATP Awards despite a stellar year from Serbian Djokovic and his tic…