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.^[1]

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, Major, ATP & Top 150 debut in singles & doubles

He reached a career-high doubles ranking of World No. 155 on 17 January 2022, after winning the 2022 Traralgon International with Zdeněk Kolář.

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 wildcards into the main draw of the 2022 French Open in singles and doubles partnering Enzo Couacaud.^[2][3]

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.^[4] He went on to defeat Michael Mmoh in the next round to reach the quarterfinals for the first time in his career.^[5] As a result, he reached the top 150 in the rankings.

2023: Return to Top 300

In July 2023, Guinard won the 2023 Internationaux de Tennis de Troyes as a qualifier, defeating fellow countryman Calvin Hemery in the final. This was Guinard's first final on the ATP Challenger Tour in more than a year, allowing him to return into the Top 300. He also won the doubles title at the same tournament.^[6]

Singles

Doubles

Singles: 14 (11 titles, 3 runners-up)

Result	W–L	Date	Tournament	Tier	Surface	Opponent	Score
Win	1–0	May 2018	Bosnia & Herzegovina F1, Doboj	Futures	Clay	Nerman Fatić	6–3, 6–4
Loss	1–1	May 2018	Sweden F3, Lund	Futures	Clay	Alexander Ritschard	3–6, 3–6
Win	2–1	Sep 2018	Netherlands F5, Rotterdam	Futures	Clay	Nik Razboršek	6–4, 7–6(7–3)
Win	3–1	Dec 2018	Tunisia F44, Monastir	Futures	Hard	Aziz Dougaz	7–5, 6–4
Loss	3–2	Mar 2019	M15 Quinta Do Lago, Portugal	World Tennis Tour	Hard	Evan Hoyt	4–6, 3–6
Win	4–2	Jun 2019	M25 Pardubice, Czech Republic	World Tennis Tour	Clay	Lukas Klein	6–4, 5–7, 7–6(8–6)
Win	5–2	Nov 2019	M15 Prague, Czech Republic	World Tennis Tour	Hard (i)	Michael Vrbenský	7–6(7–3), 6–3
Win	6–2	Dec 2019	M15 Cairo II, Egypt	World Tennis Tour	Clay	Laurynas Grigelis	6–3, 6–2
Win	7–2	Aug 2020	M25 Vogau, Austria	World Tennis Tour	Clay	Dimitar Kuzmanov	6–3, 6–3
Win	8–2	Apr 2021	M25 Angers, France	World Tennis Tour	Clay	Lucas Catarina	7–5, 6–4
Win	9–2	May 2021	M25 Prague, Czech Republic	World Tennis Tour	Clay	Jack Draper	6–4, 6–3
Loss	9–3	Jun 2021	Aix-en-Provence, France	Challenger	Clay	Carlos Taberner	2–6, 2–6
Win	10–3	Mar 2022	Roseto degli Abruzzi, Italy	Challenger	Clay	Tseng Chun-hsin	6–1, 6–2
Win	11–3	Jul 2023	Troyes, France	Challenger	Clay	Calvin Hemery	6–3, 6–3

Doubles: 23 (17 titles, 6 runners-up)

Result	W–L	Date	Tournament	Tier	Surface	Partner	Opponents	Score
Win	1–0	Dec 2017	Tunisia F40, Hammamet	Futures	Clay	Clément Tabur	Samuel Bensoussan François-Arthur Vibert	6–7(6–8), 6–2, [13–11]
Loss	1–1	May 2018	Bosnia & Herzegovina F1, Doboj	Futures	Clay	Luka Pavlovic	Christian Hirschmüller Dane Propoggia	5–7, 5–7
Win	2–1	Jul 2018	Germany F9, Wetzlar	Futures	Clay	François Musitelli	Marco Neubau Kai Wehnelt	6–1, 6–3
Win	3–1	Jan 2019	M25 Tucson, USA	World Tennis Tour	Hard	Aziz Dougaz	Lloyd Glasspool Evan Hoyt	6–4, 5–7, [10–3]
Loss	3–2	May 2019	Savannah, USA	Challenger	Clay	Arthur Rinderknech	Roberto Maytín Fernando Romboli	7–6(7–5), 4–6, [9–11]
Win	4–2	May 2019	M15 Tabarka, Tunisia	World Tennis Tour	Clay	Mariano Kestelboim	Anis Ghorbel Aziz Dougaz	6–4, 6–1
Loss	4–3	Jun 2019	M25 Pardubice, Czech Republic	World Tennis Tour	Clay	Aziz Dougaz	Vít Kopřiva Jaroslav Pospíšil	4–6, 2–6
Win	5–3	Dec 2019	M15 Cairo II, Egypt	World Tennis Tour	Clay	Laurynas Grigelis	Facundo Juarez Octavio Volpi	7–6(9–7), 6–3
Win	6–3	Feb 2020	Drummondville, Canada	Challenger	Hard	Arthur Rinderknech	Roberto Cid Subervi Gonçalo Oliveira	7–6(7–4), 7–6(7–3)
Win	7–3	Aug 2020	M25 Vogau, Austria	World Tennis Tour	Clay	Johannes Härteis	Gijs Brouwer Jelle Sels	6–4, 4–6, 11–9
Win	8–3	Mar 2021	Las Palmas, Spain	Challenger	Clay	Enzo Couacaud	Javier Barranco Cosano Eduard Esteve Lobato	6-1, 6-4
Win	9–3	Apr 2021	M25 Angers, France	World Tennis Tour	Clay	Corentin Denolly	Arthur Cazaux Titouan Droguet	Walkover
Win	10–3	Jul 2021	Amersfoort, Netherlands	Challenger	Clay	Luca Castelnuovo	Sergio Galdós Gonçalo Oliveira	0–6, 6–4, [11–9]
Loss	10–4	Sep 2021	Saint-Tropez, France	Challenger	Hard	Romain Arneodo	Antonio Šančić Artem Sitak	6–7(5–7), 4–6
Win	11–4	Jan 2022	Traralgon, Australia	Challenger	Hard	Zdeněk Kolář	Marc-Andrea Hüsler Dominic Stricker	6-3, 6-4
Win	12–4	Mar 2022	Roseto degli Abruzzi, Italy	Challenger	Clay	Franco Agamenone	Ivan Sabanov Matej Sabanov	7–6(7–2), 7–6(7–3)
Loss	12–5	Mar 2022	Zadar, Croatia	Challenger	Clay	Franco Agamenone	Zdeněk Kolář Andrea Vavassori	6–3, 6–7(7–9), [6–10]
Win	13–5	Mar 2023	Zadar, Croatia	Challenger	Clay	Nino Serdarušić	Ivan Sabanov Matej Sabanov	6–4, 6–0
Loss	13–6	Jun 2023	Troisdorf, Germany	Challenger	Clay	Grégoire Jacq	Íñigo Cervantes Oriol Roca Batalla	2–6, 6–7(1–7)
Win	14–6	Jun 2023	Lyon, France	Challenger	Clay	Grégoire Jacq	Constantin Frantzen Hendrik Jebens	6–4, 2–6, [10–7]
Win	15–6	Jul 2023	Troyes, France	Challenger	Clay	Grégoire Jacq	Álvaro López San Martín Daniel Rincón (tennis)	Walkover
Win	16–6	Jul 2023	Amersfoort, Netherlands	Challenger	Clay	Grégoire Jacq	Mats Hermans Sander Jong	6–4, 6–4
Win	17–6	Aug 2023	Meerbusch, Germany	Challenger	Clay	Grégoire Jacq	Fernando Romboli Marcelo Zormann	7–5, 7–6