Will Serena Williams win a 24th (or more) major in 2020? My guess is yes as I think she seems to be dialed in during this offseason. The talent pool she is facing is deep and comparatively younger so 2020 represents her best chance at 24 and beyond, but 4 runner-up finishes over the past two years suggest that she is close even when her preparation may not have been ideal. With preferred preparation, I think Serena Williams ties and/or exceeds Margaret Court’s record 24 singles majors even though I think holding the Open Era record already clears a major hurdle for Serena Williams.
Will Rafael Nadal tie or surpass Roger Federer’s 20 majors in 2020? Again, my guess is yes. Nadal is going to enter Roland Garros as THE favorite. Novak Djokovic and Dominic Thiem are plausible clay court threats to Nadal, but 20 seems quite likely in Paris unless he wins in Melbourne then 21 would be likely in Paris. Rafa could get lucky #13 in Paris and a possible 20th or 21st major in 2020
Will a non-Big 3 member win a major in 2020? Again, my guess is yes. Daniil Medvedev had breakpoints to start the 5th set versus Rafael Nadal at the 2019 US Open final. If he converts one of those, tennis likely would have crowned its first non-big 3 major winner since Stan Wawrinka took the 2016 US Open final. Medvedev, Stefanos Tsitsipas, Dominic Thiem, and others look closer to Grand Slam glory than any group of non-major winners has in some time. Stan Wawrinka, Marin Cilic, and even Andy Murray could also plausibly win a major in 2020 if things break a certain way. Stan could grab major #4
Will the new ATP Cup be a success? We will find out soon, but my guess is no. Debuting a new competition during an Olympic year and so close to the surprisingly well-received revamped version of Davis Cup is poor planning. Maybe some version of the ATP Cup will succeed in the long-run, but I think most players will view it as a way to hit a few balls in a competitive situation ahead of the Australian Open. The ATP Cup immediately being tied to players’ interests in an ITF-run Grand Slam event doesn’t seem like what the ATP was seeking.
Who finishes 2020 ranked #1? On the WTA side, I think Naomi Osaka grabs at least one major and the #1 ranking for 2020. On the ATP side, I think Novak Djokovic finishes a record-tying 6th year at #1 in 2020. I am not terribly confident in either prediction as both tours are brimming with depth.