Before each day of play at the Australian Open, we'll preview and predict three must-see matches. For full coverage of the season's first Slam, go to our tournament page.

Early in the tournament, Radwanska looked to me to be in major-winning form. She was playing with the confidence and quality of someone coming off a string of victories, including the biggest of her career at the WTA Finals last October. Despite that, she was very nearly sent packing in the fourth round, when Anna-Lena Friedsam led her 5-2 in the third before cramping. So where does that leave Aga now? She’s still the favorite against Suarez Navarro, but only a slight one. Radwanska leads their head to head 2-1, but CSN won their last meeting, in three sets, in Miami last spring.

Winner: Radwanska

It has, as you know, been a while since Sharapova beat Serena; 12 years, to be exact. It’s also been a while since she took a set from the world No. 1; the last time that happened was seven matches ago, in Miami in 2013. In the final here last year, Sharapova pushed the second set to a tiebreaker, but by the time they met again at Wimbledon in July, the gap was as wide as ever. Serena won, 6-2, 6-4, and Sharapova looked not only out of answers, but out of questions, too. A new season, a surface more to her liking, and 21 aces in her last match should give Sharapova a little more hope. Until it proves futile again.

Winner: Williams

Over the last half-decade, Federer has typically soared through his early matches in Oz, inspiring media and fans to make comparisons to his glory days of 2006. But each year those comparisons have been unceremoniously halted by a late-round defeat, either to Novak Djokovic, Rafael Nadal, or Andy Murray. So far, the first part of the tradition has continued in 2016; Federer was in high-flying form against David Goffin in the fourth round. Can Berdych bring him back down to earth? We know the Czech is no Nole or Rafa, but he is a little like Jo-Wilfried Tsonga, who pushed Federer to five in the quarters here three years ago.

Winner: Federer

To most fans, the lasting memory of this matchup is Nishikori’s upset win over a sluggish Djokovic in the U.S. Open semifinals two years ago. But did you know that they’ve played four matches since, and Djokovic has won them all? Twice Nishikori took a set, but their last meeting was a 6-1, 6-1 romp by Djokovic at the World Tour Finals in London in November. This match will surely be closer: Nishikori was sharp in his straight-set win over Tsonga in the last round, while Djokovic was the opposite of sharp in his five-set win over Gilles Simon. You might get one bad match per tournament from Nole, but you don’t often get two.

Winner: Djokovic