2019-2020: Grand Slam doubles debut and first win in doubles
Guinard made his Grand Slam main draw debut at the 2019 French Open after receiving a wildcard for the doubles main draw, partnering Arthur Rinderknech.
At the 2020 French Open he reached the second round for his first Grand Slam win in doubles also as a wildcard partnering Rinderknech.
2021: First Challenger final, Top 250 singles debut
He made his first Challenger final at the 2021 Open du Pays d’Aix where he lost to Carlos Taberner. He reached the top 250 on 8 November 2021 at World No. 247.
2022: Maiden challenger title, ATP debut, First two wins & quarterfinal, Top 150 debut
He reached a career-high doubles ranking of World No. 155 on 17 January 2022, after winning the 2022 Traralgon International with Zdenek Kolar.
In March, he won his maiden singles 2022 Challenger di Roseto degli Abruzzi II title as an Alternate.
In April, he made his ATP debut as a lucky loser at the 2022 Barcelona Open Banc Sabadell where he lost to Hugo Dellien. He reached a career-high singles ranking of No. 151 on 25 April 2022.
In May, Guinard was awarded a wildcard into the main draw of the 2022 French Open.
He qualified for the 2022 ATP Lyon Open main draw and defeated compatriot World No. 68 and wildcard Hugo Gaston in the first round for his first tour-level win. He went on to defeat Michael Mmoh in the next round to reach the quarterfinals for the first time in his career. As a result he reached the top 150 in the rankings.
15 Nov 1995