2009: ATP debut

In September 2009 he received wild card access to the main draw of 2009 BCR Open Romania, where he defeated his fellow countryman Victor Crivoi in the first round, but lost to Spaniard Rubén Ramírez Hidalgo in the second round.^[4]

2010–2012: Challenger Tour success

In May 2010, Copil reached his first ATP Challenger Tour final at the Trofeo Paolo Corazzi as a qualifier. On his route to the final he won in three sets against Australian Bernard Tomic in the semifinals and finished runner-up to German Denis Gremelmayr.

Season 2011 started well for Copil. He reached his second Challenger final at the Tretorn Serie+ event in Kazan, Russia. In the final, he won against 4th seeded German Andreas Beck, in straight sets.^[4]

In season 2012, Copil beat world No. 13 Marin Čilić in the first round at the China Open in Beijing.^[5]

2015–2017: Major debut, Maiden ATP doubles title, Top 100 in singles

He made his Grand Slam main draw debut at the 2015 Australian Open, where he defeated Pablo Andújar.^[4] At the same tournament, he recorded the fastest serve at a Grand Slam: 242.0 km/h (150.4 mph).^[6]

In April at the Romanian Open partnering fellow Romanian Adrian Ungur, after saving five match points, they defeated Nicholas Monroe/Artem Sitak 17–15 in the match tiebreak to become the first Romanian team to win the Bucharest title since 1998 (Pavel/Trifu).^[7][8]

At the 's-Hertogenbosch Open, Copil defeated Jarkko Nieminen and Guillermo García López as a wildcard to reach the quarterfinals.

He made his top 100 singles debut after the 2017 Mutua Madrid Open, where he was a wildcard entry, at World No. 90 on 15 May 2017.^[5][3]

2018: Two ATP singles finals

Copil reached his first ATP World Tour-level singles final at the Sofia Open, where he lost to Mirza Bašić.^[9]

Ranked No. 93, Copil reached the final of the Swiss Indoors in Basel as a qualifier, losing to Roger Federer after defeating world No. 6 Marin Čilić and No. 5 Alexander Zverev on the way, his first ever wins over top-10 players. He became the lowest-ranked Basel finalist since No. 100 Patrick McEnroe in 1994 and 1st qualifier in the final since Baghdatis in 2005.^[10]

2019: Career-high singles ranking, Grand Slam success

Copil reached the 2019 Australian Open second round for the second time defeating Marcel Granollers in straight sets. As a result, he reached a career-high singles ranking of No. 56 on 28 January 2019.^[3][2]

His best showing in doubles at a Grand Slam in his career was reaching the third round of the 2019 French Open partnering Rohan Bopanna. He also reached the second round of the 2019 US Open (tennis) for the first time in his career in singles and doubles.

2020–2023: Loss of form, drop in rankings, out of top 400

Singles: 2 (2 runners-up)

Result	W–L	Date	Tournament	Tier	Surface	Opponent	Score
Loss	0–1	Feb 2018	Sofia Open, Bulgaria	250 Series	Hard	Mirza Bašić	6–7(6–8), 7–6(7–4), 4–6
Loss	0–2	Oct 2018	Swiss Indoors, Switzerland	500 Series	Hard	Roger Federer	6–7(5–7), 4–6

Doubles: 1 (1 title)

Result	W–L	Date	Tournament	Tier	Surface	Partner	Opponents	Score
Win	1–0	Apr 2015	Romanian Open, Romania	250 Series	Clay	Adrian Ungur	Nicholas Monroe Artem Sitak	3–6, 7–5, [17–15]

Singles: 21 (8–13)

Result	W–L	Date	Tournament	Tier	Surface	Opponent	Score
Win	1–0	Aug 2007	Romania F16, Arad	Futures	Clay	Martín Alund	6–4, 6–3
Win	2–0	Aug 2008	Romania F16, Deva	Futures	Clay	Andrei Mlendea	6–3, 7–6(7–5)
Loss	2–1	Aug 2009	Romania F14, Arad	Futures	Clay	Attila Balázs	6–3, 5–7, 3–6
Loss	2–2	Oct 2009	Greece F3, Paros	Futures	Carpet	Petar Jelenic	6–2, 4–6, 6–7(2–7)
Win	3–2	Jan 2010	Guatemala F1, Guatemala City	Futures	Hard	Iván Endara	7–6(7–5), 7–6(7–3)
Loss	3–3	May 2010	Cremona, Italy	Challenger	Hard	Denis Gremelmayr	4–6, 5–7
Loss	3–4	Jan 2011	Germany F2, Stuttgart	Futures	Hard	Jan Mertl	6–2, 3–6, 4–6
Win	4–4	Feb 2011	Kazan, Russia	Challenger	Hard	Andreas Beck	6–4, 6–4
Loss	4–5	May 2011	Romania F1, Bucharest	Futures	Clay	Petru-Alexandru Luncanu	6–3, 4–6, 5–7
Loss	4–6	Feb 2012	Kazan, Russia	Challenger	Hard	Jürgen Zopp	6–7(4–7), 6–7(4–7)
Win	5–6	Feb 2013	Quimper, France	Challenger	Hard	Marc Gicquel	7–6(11–9), 6–4
Loss	5–7	Jun 2013	Arad, Romania	Challenger	Clay	Adrian Ungur	4–6, 6–7(3–7)
Loss	5–8	Jul 2013	Guimarães, Portugal	Challenger	Hard	João Sousa	3–6, 0–6
Loss	5–9	Sep 2015	İzmir, Tunisia	Challenger	Hard	Lukaš Lacko	3–6, 6–7(5-7)
Loss	5–10	Jun 2016	Surbiton, United Kingdom	Challenger	Grass	Lu Yen-hsun	5–7, 6–7(11–13)
Win	6–10	Oct 2016	Budapest, Hungary	Challenger	Hard	Steve Darcis	6–4, 6–2
Loss	6–11	Nov 2016	Bratislava, Slovakia	Challenger	Hard	Norbert Gombos	6–7(8–10), 6–4, 3–6
Loss	6–12	Oct 2017	Kaohsiung, Taiwan	Challenger	Hard	Evgeny Donskoy	6–7(0–7), 5–7
Loss	6–13	Nov 2017	Bratislava, Slovakia	Challenger	Hard	Lukáš Lacko	4–6, 6–7(4–7)
Win	7–13	Mar 2022	M25 Portimao, Portugal	World Tennis Tour	Hard	Alexey Vatutin	7–5, 6–2
Win	8–13	Jul 2023	M25 Bacău, Romania	World Tennis Tour	Clay	Hernán Casanova	6–3, 7–6(7–4)

Doubles: 19 (9–10)

Result	W–L	Date	Tournament	Tier	Surface	Partner	Opponents	Score
Win	1–0	Aug 2008	Romania F16, Deva	Futures	Clay	Ilie-Aurelian Giurgiu	Bojan Szumanski Hubert Holzler	6–3, 6–2
Win	2–0	Feb 2009	Germany F5, Nussloch	Futures	Carpet	Petru-Alexandru Luncanu	Jonathan Marray Rasmus Nørby	walkover
Win	3–0	May 2009	Romania F1, Craiova	Futures	Clay	Petru-Alexandru Luncanu	Andrei Ciumac Radu Albot	7–5, 6–1
Loss	3–1	Jul 2009	Romania F9, Iași	Futures	Clay	Victor Ioniță	Gleb Alekseenko Vadim Alekseenko	3–6, 6–2, [7–10]
Loss	3–2	Jul 2009	Romania F10, Cluj	Futures	Clay	Ilie-Aurelian Giurgiu	Gleb Alekseenko Vadim Alekseenko	4–6, 4–6
Loss	3–3	Jul 2009	Romania F11, Oradea	Futures	Clay	Ilie-Aurelian Giurgiu	Attila Balázs György Balázs	2–6, 2–6
Loss	3–4	Aug 2009	Italy F23, Bolzano	Futures	Clay	Antal van der Duim	Manuel Jorquera Leonardo Tavares	7–6(7–2), 3–6, [5–10]
Win	4–4	Aug 2009	Romania F14, Arad	Futures	Clay	Vasek Pospisil	Andrei Mlendea Jiří Školoudík	6–3, 6–4
Loss	4–5	Aug 2009	Romania F15, Brașov	Futures	Clay	Vasek Pospisil	C C-Rodriguez Gerard Granollers-Pujol	5–7, 7–6(7–2), [10–12]
Win	5–5	Jan 2010	Guatemala F1, Guatemala City	Futures	Hard	Iván Endara	James Ludlow Ruben Gonzales	7–5, 6–3
Loss	5–6	Oct 2010	Italy F30, Calabria	Futures	Clay	Giuseppe Faraone	Andrea Arnaboldi Gianluca Naso	4–6, 4–6
Win	6–6	Jan 2012	Germany F2, Stuttgart	Futures	Hard	Simon Stadler	Kevin Krawietz Marcel Zimmermann	6–1, 6–2
Loss	6–7	May 2012	Romania F2, Bucharest	Futures	Clay	Victor Crivoi	Florin Mergea Andrei Dăescu	6–7(4–7), 2–6
Win	7–7	Jun 2012	Romania F3, Bacău	Futures	Clay	Victor Crivoi	Harri Heliövaara Timo Nieminen	6–3, 6–4
Win	8–7	Sep 2012	Brașov, Romania	Challenger	Clay	Victor Crivoi	Andrei Ciumac Aleksandr Nedovyesov	6–7(8–10), 6–4, [12–10]
Loss	8–8	Jul 2014	Binghamton, United States	Challenger	Hard	Sergiy Stakhovsky	Daniel Cox Daniel Smethurst	7–6(7–3), 2–6, [6–10]
Loss	8–9	Sep 2014	Sibiu, Romania	Challenger	Clay	Alexandru-Daniel Carpen	Potito Starace Adrian Ungur	5–7, 2–6
Loss	8–10	Sep 2016	Istanbul, Turkey	Challenger	Hard	Marco Chiudinelli	Sadio Doumbia Calvin Hemery	4–6, 3–6
Win	9–10	Sep 2016	İzmir, Turkey	Challenger	Hard	Marco Chiudinelli	Sadio Doumbia Calvin Hemery	6–4, 6–4

Wins over top 10 players

#	Player	Rank	Event	Surface	Rd	Score	MC Rank
2018
1.	Marin Čilić	6	Basel, Switzerland	Hard (i)	2R	7–5, 7–6(7–2)	93
2.	Alexander Zverev	5	Basel, Switzerland	Hard (i)	SF	6–3, 6–7(6–8), 6–4	93

Singles performances (18–8)

Edition	Round	Date	Against	Surface	Opponent	Win/Lose	Result
2009 World Group play-offs	PO	18–20 September 2009	Sweden	Hard (i)	Andreas Vinciguerra	Win	4–6 ret.
2010 Europe/Africa Zone Group I	QF	7–8 May 2010	Ukraine	Clay	Ivan Sergeyev	Unfinished	4–6, 2–1
2011 World Group play-offs	PO	16–18 September 2011	Czech Republic	Clay	Lukáš Rosol	Lose	4–6, 6–7(2–7)
2012 Europe/Africa Zone Group I	1R PO	14–16 September 2012	Finland	Hard (i)	Harri Heliövaara	Win	3–6, 6–4, 6–2, 6–4
					Jarkko Nieminen	Lose	3–6, 5–7, 6–1, 6–7(4–7)
2013 Europe/Africa Zone Group I	1R	1–3 February 2013	Denmark	Hard (i)	Frederik Nielsen	Win	6–3, 7–6(9–7), 6–4
					Christoffer Kønigsfeldt	Win	6–4, 6–3
	2R	5–7 April 2013	Netherlands	Hard	Thiemo de Bakker	Lose	6–7(3-7), 6–7(2–7)
2014 Europe/Africa Zone Group I	1R PO	12–14 September 2014	Sweden	Clay	Elias Ymer	Win	6–2, 6–3, 6–2
2015 Europe/Africa Zone Group I	1R	6–8 March 2015	Israel	Hard (i)	Dudi Sela	Win	6–7(3–7), 7–6(7–3), 6–4, 6-2
					Bar Tzuf Botzer	Win	7–6(7–3), 6–3
	2R	17–19 July 2015	Slovakia	Clay	Norbert Gombos	Win	7–6(7–5), 6–7(6–8), 6–4, 7–6(12–10)
					Martin Kližan	Lose	7–6(7–3), 6–3
2016 Europe/Africa Zone Group I	1R	4–6 March 2016	Slovenia	Hard (i)	Blaž Rola	Win	7–5, 6–3, 7–6(7–5)
					Tomislav Ternar	Win	6-3, 6–3
	2R	15–17 July 2016	Spain	Hard	Feliciano López	Lose	6–7(7-7), 7–5, 4–6, 6–3, 3–6
2017 Europe/Africa Zone Group I	1R	3–5 February 2017	Belarus	Hard (i)	Egor Gerasimov	Lose	3–6, 4–6, 4–6
					Ilya Ivashka	Win	7–5, 6–3, 6–1
2018 Europe/Africa Zone Group II	1R	3–4 February 2018	Luxembourg	Hard (i)	Christophe Tholl	Win	6-3, 6-2
					Ugo Nastasi	Win	6-1, 6-1
	2R	7–8 April 2019	Morocco	Hard (i)	Amine Ahouda	Win	6-0, 6-1
	3R	15–16 September 2019	Poland	Clay (i)	Kamil Majchrzak	Win	6-2, 6-4
					Hubert Hurkacz	Lose	3-6, 4-6
2019 Europe/Africa Zone Group II	—	5–6 April 2019	Zimbabwe	Hard (i)	Benjamin Lock	Lose	4-6, 5-7
					Takanyi Garanganga	Win	6-4, 7-5
2020–2021 World Group I	PO	17–19 September 2021	Portugal	Hard (i)	Gastão Elias	Win	6-4, 6-3
					Gastão Elias	Win	6–3, 2–6, 6–4

Doubles performances (2–1)

Edition	Round	Date	Partner	Against	Surface	Opponents	Win/Lose	Result
2009 World Group	1R	6–8 March 2009	Horia Tecău	Russia	Hard (i)	Marat Safin Dmitry Tursunov	Win	4–6, 6–7(2–7), 7–6(7–4), 7–6(7–5), 6–4
2011 World Group play-offs	PO	16–18 September 2011	Horia Tecău	Czech Republic	Clay	Tomáš Berdych Radek Štěpánek	Lose	6–3, 3–6, 0–6, 2–6
2014 Europe/Africa Zone Group I	1R	31 January – 2 February 2014	Horia Tecău	Ukraine	Hard	Sergei Bubka Denys Molchanov	Win	5–7, 6–3, 6–4, 6–4