The US Open starts on Monday at Flushing Meadows, with defending champions Novak Djokovic and Coco Gauff in action, along with former champions Dominic Thiem and Sloane Stephens.AFP Sport looks at three matches to watch on Monday: Radu Albot (MDA) v Novak Djokovic (SRB x2) — Serbian superstar Djokovic, fresh off a longed-for Olympic gold medal in Paris, appears poised to ease his way into his US Open title defense with a first-round meeting against qualifier Albot.