Two unseeded former Grand Slam champions are in action as first-round play continues on Day 2 of the Miami Open. In addition, two former Top 30 players return after injury lay-offs and two standout juniors make their WTA 1000 debuts.

Naomi Osaka (JPN) vs. Astra Sharma (AUS)

This tournament has rarely been a happy hunting ground for Osaka. The four-time major champion has winning percentages of over 70% at the Australian Open, US Open, Indian Wells and Cincinnati, but just 58% in Miami. Her best showing was a quarterfinal run last year, but even that saw her 23-match winning streak unceremoniously ended by Maria Sakkari 6-0, 6-4.

Osaka's comeback after her mental health struggles in 2021 has delivered some quality wins so far, notably over Sloane Stephens in the first round of Indian Wells. But she will be seeking to recover from an unfortunate second-round loss to Veronika Kudermetova, in which the 24-year-old was rattled by a heckler in the crowd.

No.96-ranked Sharma, who won her maiden title at the Charleston 250 last April, has had a slow start to 2022 with a 3-7 record so far, but put up a spirited fight against Victoria Azarenka in the second round of Indian Wells.

Head-to-head: 0-0.

Miami Open: Order of PlayDraw | 411

Panna Udvardy (HUN) vs. Sloane Stephens (USA)

Stephens is one of only two former Miami champions in this year's field alongside Victoria Azarenka, and the most recent after lifting the trophy in 2018. The American snapped a title drought dating back to that win when she was victorious in Guadalajara last month, but fell to Naomi Osaka in the first round of Indian Wells.

Udvardy's rise from No.352 at the start of 2021 to her present No.83 has flown under the radar somewhat, largely due to the Hungarian's biggest successes coming at WTA 125 level at the end of last year. After winning 73 matches in 2021, Udvardy has had a less auspicious start to this season: she is 0-6 in 2022 so far, and fell in the first round of Indian Wells qualifying to 17-year-old wildcard Ashlyn Krueger.

Head-to-head: 0-0.

Best of the rest

Alison Riske and Jil Teichmann have both bolstered their reputations as upset artists this year: Teichmann has scored wins over Angelique Kerber (in Doha) and Elina Svitolina (in Dubai), while Riske overcame a 6-0, 3-0 deficit to stun Garbiñe Muguruza in Indian Wells. Moreover, the pair played a superb match in the first round of Ostrava last year, won by Teichmann 6-3, 1-6, 6-4, in which the Swiss player's speed and touch proved an entertaining foil to Riske's flat hitting.

Clara Tauson, 19, has solidified her position as a rising star on tour, but is still seeking her first deep run above WTA 250 level. The Dane, who also took Swiatek to three sets in Indian Wells, opens against Lyon champion Zhang Shuai in a first-time encounter.

Former World No.19 Karolina Muchova has not competed since last year's US Open due to an abdominal injury, and after being unable to defend her 2021 Australian Open semifinal points saw her ranking fall to No.74. The Czech faces a tough test off the bat in compatriot Tereza Martincova, whose elegant shotmaking has scored her wins over Svitolina, Jelena Ostapenko and Anastasia Pavlyuchenkova in the past year.

Also on the comeback trail is former World No.27 Laura Siegemund, who was sidelined for seven months after the Tokyo Olympic Games due to a knee injury. The German played the Porto ITF W25 and Lyon qualifying in February, and returns to WTA main draw level against qualifier Marie Bouzkova. 

Top 10 juniors Linda Fruhvirtova and Alexandra Eala both make their WTA 1000 debuts via wildcard. Fruhvirtova, 16, reached her first WTA quarterfinal at the Charleston 250 last April and won her first ITF W25 title in Cancun last month. The No.279-ranked Czech opens against Danka Kovinic, fresh off upsetting Karolina Pliskova in Indian Wells two weeks ago.

Eala became the first Filipina ever to win a WTA main draw match when she defeated Paula Ormaechea in Cluj-Napoca last August; now ranked No.565, the 16-year-old starts against the experienced Madison Brengle.

Teichmann overcomes Riske in 3 sets to round out Ostrava quarters: Highlights