Marta Kostyuk (UKR): first week in the top 10 — up to No. 10, from a previous best of No. 11, in the week of September 14, 2026. Here is the road, from the record.
It began in August 2016: Lost to Ploskina in the first round at Kharkiv, with no ranking to speak of.
The steps came in this order: first ITF title in May 2017; Grand Slam qualifying debut in January 2018; Grand Slam main-draw debut in January 2018; first week in the top 300 in January 2018; first week in the top 250 in January 2018; first tour-level main draw in April 2018 (No. 156 at the time); first week in the top 100 in November 2020; first week in the top 50 in November 2021; first WTA 125 main draw in December 2022 (No. 71 at the time); first tour-level title in March 2023 (No. 55 at the time); first week in the top 20 in May 2024.
From the first recorded match to the top 100 took 4 years and 3 months.
Today Kostyuk is ranked No. 10, with 189 weeks inside the top 500 on record.
Nobody on Unseeded was following Kostyuk before this week. The next one is out there.