Before each day's play at the 2020 Australian Open, we'll preview three must-see matches.
Daniil Medvedev  vs. Frances Tiafoe
When Tiafoe chest-thumped his way to his first Grand Slam quarterfinal here last year, it looked as if the young American was on his way to a breakthrough season. The same was true of Medvedev, who reached the fourth round and gave Novak Djokovic the only decent test he would face all tournament. But the breakthrough only came for one of these two men, and you can see it in their current rankings—Tiafoe is treading water at No 49, while Medvedev is perched at a stratospheric No. 4. In their only previous ATP-level meeting, Medvedev won in straight sets at the 2019 Citi Open, an event that kick-started his second-half surge. The Russian will be solidly, if not heavily, favored, to do it again. But don’t count Tiafoe out; he’s not going to want to cede all of those quarterfinal ranking points without a fight.
Simona Halep  vs. Jen Brady
You win some, you lose some: Halep will likely be happy to have landed in the half of the draw that doesn’t include Serena Williams, Ash Barty, Petra Kvitova or Naomi Osaka. But she probably won’t be happy with who she has to face in the first round. Brady is the type of free-swinging hard hitter who traditionally gives the defensive-minded Halep fits. The last time they played, Brady gave her more than one: At the 2019 Rogers Cup, the American pushed the Romanian all the way to a third-set tiebreaker. Add to that the fact that a fitter-looking Brady already has wins over Maria Sharapova and Barty this year, while Halep lost last week to Aryna Sabalenka in straight sets last week, and we should probably put this match on early upset alert. But with old coach Darren Cahill back on her team, I’ll stick with the favorite.
Rafael Nadal  vs. Hugo Dellien
All signs point to smooth opener for Rafa. Dellien, a 26-year-old from Bolivia, is ranked a career-high No. 72, and he plays as many matches as he can on clay courts. At the very least, it will take some time for him to adjust and find his range on the hard stuff inside Rod Laver Arena, in what will likely be a night-session showcase. Nadal, meanwhile, seems to be healthy—and when he plays an unseeded opponent, that’s usually all you need to know.