MADRID—Novak Djokovic is still uncertain whether he will take part in the 2022 Australian Open but will soon make a decision, the world number one said after Serbia’s 2–1 defeat by Croatia in the Davis Cup semifinals on Friday. Djokovic, 34, has repeatedly declined to reveal whether he has been vaccinated against COVID-19, with his father Srdjan telling Serbia’s Prva television last week that the world’s top- ranked player would probably pull out of the tournament. “I know what you want to ask but I am not going to give you an answer tonight,” Djokovic told a virtual news conference after a question about when he might be expected on court again. “Obviously, Australia is just around the corner so you’ll know very soon. “I will use the next days to recover and forget about tennis. I am really tired from this season and this whole year. I need some …