Viktor Troicki

From 2003, he started playing Futures tournaments in Serbia and in 2004, won his first tennis tournament in Niš, thereafter his first Challenger tournament in Belgrade on 20 January 2005 versus Fabio Colangelo 6–2, 6–1 in the final.

As a junior, Troicki compiled a singles win/loss record of 68–31 (52–20 in doubles) and reached a combined ranking of No. 10 in the junior world rankings in October 2004.

He debuted on the ATP Tour in Tokyo, in October 2006, with a first round win over Fernando Vicente 6–7, 6–4, 6–2, before narrowly losing in the next round to recent world No. 1 Roger Federer 6–7, 6–7.

In July 2007, as a qualifier in the Umag Croatian Open, he overwhelmingly upset world No. 3 and fellow countryman Novak Djoković in the second round 2–6, 6–4, 7–5, before eventually losing to Romanian Andrei Pavel in the semi-final.

In January 2009, he lost in first round of the Qatar Open to Victor Hănescu and in the quarterfinals to del Potro. In second round of the Australian Open, he was crushed by Tommy Robredo, 6–1, 6–3, 6–0. After that, Troicki made a good result in the Zagreb Indoors. He lost in the semifinals to Marin Čilić, 2–6, 5–7. Also in February, Troicki won the GEMAX Open, a Tretorn Serie + Challenger held in Belgrade. In the final, he defeated Dominik Hrbatý in two sets.

In March 2009, Troicki played for the Serbian Davis Cup team, losing to David Ferrer 0–6, 3–6. He then competed in the next four Masters Series. In the BNP Paribas Open, he lost to David Nalbandian in the third round 4–6, 2–6. In the Miami Masters, he reached the fourth round before Andy Murray defeated him 6–1, 6–0. He then lost in the first round to Stan Wawrinka in the Monte Carlo Masters, and in the Rome Masters to Juan Martín del Potro in the second round. Viktor competed in the first tournament of his home nation in the Serbia Open, losing to compatriot Novak Djokovic. In the Madrid Masters, he lost to Nikolay Davydenko 2–6, 2–6, in the opener. He then represented Serbia in the ARAG World Team Cup, helping Serbia to win the title by beating Rainer Schüttler in the finals. In the French Open, he lost to fifth seed and eventual semifinalist Juan Martín del Potro in the second round 3–6, 5–7, 0–6, after defeating Łukasz Kubot in a tight five-setter 3–6, 6–3, 6–4, 6–7, 6–3, a match that lasted 3 hours and 58 minutes.

Troicki was seeded for the first time in a Grand Slam tournament in Wimbledon Championships, as 30th seed, beating Brian Dabul in straight sets in the first, and winning a five-setter against Daniel Gimeno-Traver in the second round. He lost to Andy Murray in the third round. He then competed in the German Open in Hamburg, losing to eventual finalist Paul-Henri Mathieu 0–3 ret., in the quarterfinals due to a foot injury he suffered when he fell hard in the start of the match. He then lost to Máximo González in Umag in the first round 4–6, 6–3, 6–7. He lost to Marc Gicquel in the second round of the Legg Mason Tennis Classic, 0–3 ret., due to his recurring foot injury suffered in Hamburg after receiving a bye in the first round. He then lost to Ferrer in the first round of the Rogers Masters 3–6, 0–6, and retired in the first round of the Western & Southern Financial Group Masters against Radek Štěpánek, 7–6, 1–0 ret. He had recorded five straight loses. Troicki competed in the US Open as 30th seed and claimed his first victory since Hamburg, defeating Peter Luczak 6–3, 6–3, 1–6, 2–6, 6–1, in the first round, but lost to Julien Benneteau in the following round. He then competed in the 2009 Davis Cup Play-offs, where he won both his matches against Uzbekistan.

Troicki reached another final in the Thailand Open. After defeating Thomaz Bellucci, 6–3, 7–6 in the round of 16, he then defeated eighth-seeded American John Isner 7–6, 6–2, in the quarterfinals. In his semifinal match, he went on to upset the defending 2008 Bangkok champion, 2008 Australian Open finalist, and top seed Jo-Wilfried Tsonga, 1–6, 6–2, 6–3 to reach his second ATP World Tour final to face the second seeded Gilles Simon. He lost 5–7, 3–6. He then competed in the 2009 China Open, where he lost in the second round to compatriot and eventual champion Novak Djokovic 3–6, 0–6. He then competed in the Shanghai ATP Masters 1000, where he lost to eighth seed Gilles Simon, 3–6, 4–6, after defeating Juan Mónaco 6–1, 6–2, in the first round. He was then upset by Karol Beck in the first round of the St. Petersburg Open, marking his 10th first-round loss in 25 tournaments. He then defeated Benjamin Becker 6–2, 7–6, before losing to Marin Čilić in the second round in a close three setter 6–7, 7–6, 6–7, in the Swiss Indoors. He played his last tournament in the BNP Paribas Masters, losing in the second round to Radek Štěpánek 4–6, 2–6, after defeating Paul-Henri Mathieu 7–6, 3–0 ret.

In the start of the clay season, Troicki competed in the Monte-Carlo Masters, losing to 12th seed Tommy Robredo in the second round, after defeating Łukasz Kubot 4–6, 6–2, 6–2. In October 2010, Viktor won his first ATP World Tour title in Moscow, defeating Marcos Baghdatis in the final 3–6, 6–4, 6–3. On his road to the title, he had also eliminated Dmitry Tursunov, Jo-Wilfried Tsonga, Horacio Zeballos, and Pablo Cuevas.

Troicki was part of Serbia's Davis Cup team that reached the final for the first time in their history in 2010. He was initially overlooked for the singles rubbers, but after compatriot Janko Tipsarević was beaten by Gaël Monfils in straight sets, Troicki was chosen to play the final singles rubber, as well as the doubles. With Serbia and France tied at 2–2, Troicki won the deciding match 6–2, 6–2, 6–3, against Michaël Llodra to clinch Serbia's first Davis Cup, a triumph labeled by national coach Bogdan Obradovic as "the greatest sporting triumph in Serbia's history".

Troicki started 2011 in ATP Doha, where he lost to Roger Federer 2–6, 2–6, in the quarterfinals. Troicki advanced to the finals at ATP Sydney, where he beat Juan Ignacio Chela, Richard Gasquet, Florian Mayer, and in the final, lost to Gilles Simon 5–7, 6–7. Then at the Australian Open, he reached the third round for the first time, but retired against compatriot and eventual champion Novak Djokovic due to a stomach pain, after losing the first set 2–6. He next played at the ABN AMRO World Tennis Tournament and reached the semifinals without dropping a set, but fell to Robin Söderling 5–7, 4–6. He then fell to Philipp Kohlschreiber 1–6, 6–7, in the first round of the Dubai Tennis Championships. He represented Serbia in the first round of 2011 Davis Cup and won both his matches. He then played the Masters 1000 events, the BNP Paribas Open and the Sony Ericsson Open, falling to eventual champion Novak Djokovic in the fourth round in both tournaments. He then reached his first Masters 1000 quarterfinals at the Monte-Carlo Masters, losing to David Ferrer 3–6, 3–6, after his opponent in the previous round Tommy Robredo retired while leading the match 6–3, 1–2. He then suffered early losses in the Serbia Open, the Madrid Open, and the Italian Open. Troicki then represented Serbia in the World Team Cup, winning his matches against Mikhail Youzhny and Marcel Granollers, but losing his match to Florian Mayer. At the French Open, Troicki reached his first Grand Slam fourth round with wins over Julian Reister, Tobias Kamke, and Alexandr Dolgopolov. In the fourth round, he faced fourth seed Andy Murray, where he lost 6–4, 6–4, 3–6, 2–6, 5–7, despite serving for the match at 5–3 and 30–0 in the final set in a match that was played over two days. He then reached a new career high of no. 12.

In 2012 with only two quarterfinal appearances, this season compared to previous seasons' individual results were sub-par, however his contributions to the Serbian national team did result in winning the World Team Cup along with a third consecutive quarterfinal appearance at the Davis Cup.

Troicki won the Boodles Challenge, a warm-up to Wimbledon exhibition, defeating Robin Haase 7–5, 6–4 in the final. On 25 July 2013, Troicki was banned from playing tennis for 18 months, for failing to provide a blood sample at the Monte-Carlo Masters event. However, the suspension was reduced on appeal to one year, meaning he could play from 15 July 2014. After the Court of Arbitration for Sport announced their decision, Troicki, who had hoped his suspension would be overturned, said that he has "no idea about what to do now or where to go. I hope somehow I will be able to fight back."

At the Apia International in Sydney in January 2015, Troicki defeated Gilles Müller 6–2, 6–4 in the semifinals en route to defeating Mikhail Kukushkin 6–2, 6–3 in the finals to capture his second career title. In the first ATP final in history featuring two qualifiers, Troicki dispatched Kukushkin in 64 minutes after breaking the Kazakh twice in each set. This victory brought him 38 positions up on ATP ladder to the position of 54 prior to the Australian Open. At Australian Open, he made it to third round before being eliminated by world No. 7, Tomas Berdych in straight sets. In March, Troicki defeated young Croatian prodigy Borna Ćorić in five epic sets in round one of Davis Cup; Serbia would go on to win & progress to the quarterfinals. After defeating Marin Čilić on 14 June, Troicki played in the finals of Stuttgart Mercedes Cup versus Rafael Nadal. Troicki played very well but Nadal won in straight sets, 7–6, 6–3. His US Open campaign opened with a straight sets victory over Frances Tiafoe and a 3–1 win over Rajeev Ram.

He married Aleksandra (née Đorđević) on 27 November 2016. They have two daughters, Irina and Darija.

In June 2020, Troicki and his then-pregnant wife tested positive for COVID-19.