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.[5]
In season 2012, Copil beat world No. 13 Marin Čilić in the first round at the China Open in Beijing.[6]
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.[5] At the same tournament, he recorded the fastest serve at a Grand Slam: 242.0 km/h (150.4 mph).[7]
At the 2015 Romanian Open in April, 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).[8][9]
Copil reached his first ATP World Tour-level singles final at the Sofia Open, where he lost to Mirza Bašić.[10]
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.[11]
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.[1][4]
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 for the first time in his career in singles and doubles.
Copil currently resides and trains in his hometown Arad, Romania.
He got married with his long-term girlfriend Ramona in 2018. His first son Arthur was born in 2020.
Besides playing professional tennis Copil also enjoys playing football, watching moto GP, collecting watches and he is an amateur photographer. Marius currently has a dog named Alex Bogdan.[12][13]
(W) winner; (F) finalist; (SF) semifinalist; (QF) quarterfinalist; (#R) rounds 4, 3, 2, 1; (RR) round-robin stage; (Q#) qualification round; (P#) preliminary round; (DNQ) did not qualify; (A) absent; (Z#) Davis/Fed Cup Zonal Group (with number indication) or (PO) play-off; (G) gold, (S) silver or (B) bronze Olympic/Paralympic medal; (NMS) not a Masters tournament; (NTI) not a Tier I tournament; (P) postponed; (NH) not held; (SR) strike rate (events won / competed); (W–L) win–loss record.
To avoid confusion and double counting, these charts are updated at the conclusion of a tournament or when the player's participation has ended.
Romania
Mirza Bašić
Roger Federer
Nicholas Monroe
Artem Sitak
Martín Alund
Attila Balázs
Petar Jelenic
Iván Endara
Denis Gremelmayr
Jan Mertl
Jürgen Zopp
Marc Gicquel
João Sousa
Lukaš Lacko
Lu Yen-hsun
Steve Darcis
Evgeny Donskoy
Bojan Szumanski 
Hubert Holzler
Jonathan Marray 
Rasmus Nørby
Andrei Ciumac 
Gleb Alekseenko 
Antal van der Duim
Manuel Jorquera 
Vasek Pospisil
C C-Rodriguez 
Harri Heliövaara 
Sweden
Israel
Slovenia
Belarus
Luxembourg
Morocco
Zimbabwe
