Returning guest Joe Posnanski is the author of the Baseball 100, and he writes about all sports at JoeBlogs on Substack. We talk about the Australian Open--what it means for Rafa's case as the greatest of all time, if we'll ever forget about the saga that kept Djokovic out of the tournament, how Daniil Medvedev stacks up against the rest of the field, whether Ashleigh Barty is pulling away from the WTA pack, and which other women we're expecting to see emerge to challenge her. We also dive into the general subject of Greatest-of-All-Time lists, the subject of Joe's book, his current American football project, and my just-launched Tennis 128. We consider how tennis greatness differs from that of other sports, how to handle career gaps such as wars and injuries, and balancing algorithms with gut feelings. We wrap up by giving Joe a speed round of tennis GOAT questions, one toughie after another asking him to untangle the trickiest debates in the sport's history.