Kayla Day

Kayla Day (born September 28, 1999) is an American professional tennis player. She has a career-high singles ranking of world No. 84 by the WTA. As a junior, she won one junior Grand Slam title, at the 2016 US Open. There, she finished runner-up in the doubles event, partnering with Caroline Dolehide.

Despite having success as junior, Day has mostly spent time playing on the ITF Women's Circuit instead of WTA Tour, due to her ranking. She officially turned professional in 2017, at the Australian Open.

Early life and background
Day started playing tennis when she was seven years old. Her mother is from the Czech Republic.

Junior career
She was No. 1 in the girls' 12s, 14s, 16s, and 18s national US rankings. In 2016, Day climbed to the top of the ITF junior rankings by winning the 2016 Junior US Open, reaching semifinals at the 2016 Wimbledon, and reaching the final at the Orange Bowl the previous year. She also achieved her best doubles result at a major event as a runner-up at the 2016 Junior US Open with partner Caroline Dolehide. She won the 2016 USTA Girls 18s National Championships to earn a wildcard into the main draw of the US Open. Day has been coached from the beginning by Larry Mousouris, who has coached two other Junior US Open winners (Michael Falberg and Tim Trigueiro).

2016-2017: Turned professional, first title, Grand Slam & Premier-level debut
Day made her WTA Tour debut at the Connecticut Open in New Haven, after reaching the main draw as a lucky loser, having defeated Naomi Broady and Kirsten Flipkens along the way. The following week, she played in her first career Grand Slam at the US Open, and won her first match against compatriot Madison Brengle.

Shortly after turning 17, Day won her first career title at the $50k tournament in Macon, Georgia. The following week at Scottsdale, she reached the semifinals to enter the top 200 for the first time. With her combined performance at these two events, she won the Australian Open Wild Card Challenge to earn a spot in the main draw at the first major event of 2017.

Day picked up her first tour wins of the season — and first wins of her career at a Premier Mandatory event — at the 2017 Indian Wells Open, including a victory over 2017 Australian Open semifinalist Mirjana Lučić-Baroni to reach the third round of the tournament.

2022: WTA 1000 debut
After almost five years of absence at the WTA 1000 level, she qualified for the main draw at the Guadalajara Open where she lost in the first round to Eugenie Bouchard.

2023: French Open debut and third round, top 100
Day won three matches in the French Open qualifying to make her first main draw at Roland Garros, as well as her first Grand Slam tournament appearance since the 2017 US Open. She defeated wildcard Kristina Mladenovic and 20th seed Madison Keys to reach the third round of a major for the first time.

She reached the top 100 on 24 July at world No. 94.

2024
At the Australian Open, she lost to Viktoriya Tomova in the first round.

At the Indian Wells Open, she entered the main draw as a lucky loser replacing fourth seed and defending champion, Elena Rybakina, directly in the second round.

Performance timelines
Only main-draw results in WTA Tour, Grand Slam tournaments, Billie Jean King Cup, United Cup, Hopman Cup and Olympic Games are included in win–loss records.

Singles
Current through the 2023 Korea Open.