Jannik Sinner said he's not the only tennis player who's tweaking his game at a press conference Thursday ahead of the Shanghai Masters after last Sunday's return to winning ways in Beijing following his US Open defeat to great rival Carlos Alcaraz.     Since winning the final in Beijing against American Learner Tien, the 24-year-old four-time major winner and former world number one has had little time to reset, but he appeared confident in his press conference upon his arrival in the Chinese