It's been a tough start for most of the top women, but Angelique Kerber and Victoria Azarenka led the way with big wins and exciting encounters.
Here's a look at our first-quarter grades on the WTA Tour.
No. 1 Serena Williams: B
It has been an unexceptional period for the No. 1, who has not won a title since August. Williams did reach the final of the Australian Open and Indian Wells, but last week, she fell in the quarterfinals of the Miami Open. It did take three very good players -- Kerber, Azarenka and Svetlana Kuznetsova -- to stop Williams, who seemed bothered by either movement or nerves (or both) in those matches.
No. 2 Angelique Kerber: A-
Winning the Australian Open caps anything else she had ever accomplished, so Kerber's season would still have been considered a success even if she hadn't won another match. And for a while it looked like she might not. Outside Fed Cup, the 28-year-old German didn't win another match until Miami, where she reached the semifinals.
No. 3 Agnieszka Radwanska: B+
Radwanska carried her fine form from the WTA Championships into this season, winning her first event in 2016 and then reaching the semifinals of the Australian Open, Doha and Indian Wells. But it should be noted Radwanska has only one win against a player inside the top 10 this season.
No. 4 Garbine Muguruza: C+
There have been matches in which Muguruza just hasn't showed up, such as her loss in the third round in Australia and her opener at Indian Wells. But she played high-quality matches in Miami, including a 7-6 (6), 7-6 (4) loss against Azarenka in the quarterfinals.
No. 5 Victoria Azarenka: A
She won Brisbane and lost to eventual champion Kerber in the Aussie Open quarterfinals. Then Azarenka swept the spring hard-court circuit at Indian Wells and Miami, making her hottest player in 2016.
No. 6 Simona Halep: C+
She started the season with illness and injury and was stunned in the first round of the Australian Open. Halep then announced she would have nose surgery, only to postpone it and begin playing again. The Romanian did play better in the past month, reaching the quarters at both of the Tier 1 spring events.
No. 7 Petra Kvitova: C+
She stopped working with longtime coach David Kotyza after the Australian Open, saying she wanted to keep improving her game, but it hasn't happened yet. Kvitova, a two-time Grand Slam champion, began the season with a stomach illness and has won more than one match at a single event just once this season.
No. 8 Roberta Vinci: B
Vinci has ridden her famous win against Serena Williams at last year's US Open to a top-10 ranking and the biggest title of her career, in St. Petersburg. But Vinci, 33, retired with a foot injury in Indian Wells and lost her second match in Miami.
Biggest gainers
No.13 Svetlana Kuznetsova: The two-time Grand Slam champion won Sydney and reached the Miami final to re-emerge from the rankings wilderness.
No. 21 Johanna Konta: She kick-started her season with a run to the Aussie semifinals and has played consistently well all season long.
No. 36 Daria Kasatkina: The 18-year-old halved her ranking since starting the season with a win against Venus Williams in Auckland. And it's taken a top-20 player to beat her at every event she's played since the Australian Open.
No. 64 Zhang Shuai: Her plan was to play the Australian Open, then hang up her racket. But Zhang beat Halep in the first round, reached the quarterfinals as a qualifier and hasn't looked back.