Jakub Mensik was born in Prostejov, Czech Republic on September 1, 2005. His parents are Michal and Katerina Mensikova. Mensik started playing tennis at age five on the public courts near his home. He learned different techniques and strategies by observing adults playing on the courts.
After showing a tennis talent, Mensik started working with coach Ivo Müller. In 2020, Mensik started competing at the junior level and he reached 11th in the junior rankings in 2021. He also made the boys' Australian Open final in 2022 but suffered an injury in the final and lost against Bruno Kuzuhara.
Mensik progressed to Challenger level in 2023 and had near-immediate success. At the 2023 Sparta Prague Open, aged just 17, he defeated Dominik Koepfer in the final. Despite the triumph, Mensik continued to play at Challenger level in 2023 and made his Grand Slam debut at the US Open. Here, he beat Gregoire Barrere in round one and Titouan Droguet in round two. However, the Czech teenager then fell to Taylor Fritz in round three.
Mensik made a solid start to 2024 by reaching his second Challenger final in Canberra but lost the final match against Dominik Koepfer. He also reached his first-ever Australian Open main draw after navigating qualifying. In the first round, Mensik defeated Denis Shapovalov before falling in the second round.
Now established on the ATP Tour, Mensik kept improving. In February 2024, he reached his first final at an ATP event at the Qatar Open. On his way to the final, Mensik beat Andy Murray, Andrey Rublev, and Gael Monfils. However, he lost against Karen Khachanov in the final. Mensik made his Masters debut at the 2024 Indian Wells main draw and beat Hong Seong-chan in the first round.
