Luca Van Assche

In 2021, Van Assche had remarkable results on ITF junior circuit. He won the boys' singles title at the 2021 French Open, defeating countryman Arthur Fils in the final. He reached an ITF junior combined ranking of world No. 1 on 5 July 2021.

In January 2022, ranked No. 445, Van Assche received a wildcard for the qualifying event at the 2022 Open Sud de France but lost to Roman Safiullin. He also made his ATP main draw doubles debut after receiving a wildcard into the main draw with Sascha Gueymard Wayenburg where they defeated David Vega Hernández and Denys Molchanov to win their first ATP tour level match. He also made his Grand Slam debut in doubles at the French Open as a wildcard pair partnering also Gueymard Wayenburg.

In October, Van Assche reached his first singles final on the ATP Challenger Tour in Lisbon, Portugal, entering the main draw as a qualifier and losing to Marco Cecchinato in the finals. As a result he broke into the top 250. The following week, he made his ATP singles debut in Antwerp after qualifying for the main draw.

On 14 November 2022, he entered the top 200 at world No. 198, after reaching the final of the Brest Challenger losing to Grégoire Barrère and the quarterfinals in Roanne. In December, Van Assche won his maiden Challenger title in Maia defeating qualifier Maximilian Neuchrist in the final. As a result he moved to No. 138 in the rankings, making him the youngest player in the top 150.

Van Assche received a wildcard into the 2023 Australian Open main draw to make his Grand Slam tournament debut in singles, losing in the first round to 11th seed Cameron Norrie.

Van Assche competed at the Teréga Open Pau–Pyrénées, a 125-level event, where he won his second Challenger title. In the final match, he defeated countryman Ugo Humbert in three hours and 56 minutes, which set a record for the longest ATP Challenger final. As a result, he moved close to 40 positions up and reached the top 110 on 6 March 2023. Following his third Challenger title at the 2023 Sanremo Challenger, Italy, he reached No. 91 on 3 April 2023 making him the youngest player in the top 100 that time. The next week, he recorded his first ATP win at the Estoril Open over qualifier Pedro Sousa after entering into the main draw directly. He lost his next match to third seed Alejandro Davidovich Fokina.

Van Assche recorded his first top-100 win over Swiss Stan Wawrinka at the Srpska Open, before losing to world No.1 Novak Djokovic in the second round.

Van Assche recorded his first major win at the French Open defeating Marco Cecchinato in the first round before losing to 29th seed Alejandro Davidovich Fokina in the second round. He made his Wimbledon debut in July, losing to Aslan Karatsev in the first round. At Wimbledon, Van Assche recorded his first Grand Slam doubles win, playing along with fellow countryman Arthur Fils, defeating brothers Stefanos Tsitsipas and Petros Tsitsipas in the first round.

In November, he qualified for the Next Generation ATP Finals where wins over Abedallah Shelbayh and Alex Michelsen were enough for Van Assche to advance from his group into the semifinals despite a defeat to Hamad Medjedovic. He lost in the last four to top seed Arthur Fils.

At the Australian Open, Van Assche reached the third round defeating James Duckworth and 25th seed Lorenzo Musetti, before losing to seventh seed Stefanos Tsitsipas. Later that season, he qualified for another edition of NextGen Finals, where he equalled his best result at the previous year, reaching the semifinals. He lost to eventual champion João Fonseca in straight sets.

In May 2025, ranked No. 211, Van Assche reached his first Challenger final in more than two years at the 2025 Zagreb Open, losing to Dino Prižmić in the final. In October, Van Assche won his first Challenger title in more than two years at the Olbia Challenger 125, defeating Pablo Carreño Busta in the final.

In February 2026 he won his fifth title at the Quimper Open Bretagne Occidentale 125 Challenger and moved back close to the top 125 on 2 February 2026.