Naomi Osaka makes her comeback to Grand Slam tennis on day two of the Australian Open Monday, while Daniil Medvedev has vowed to turn over a new leaf and be "more mature" on court."I have a much more positive mindset and a much more grateful mindset," four-time Grand Slam champion Osaka said of returning to Melbourne, the scene of her title-winning exploits in 2019 and 2021.