Martin Kližan (; born 11 July 1989) is a Slovak former professional tennis player. The winner of the 2006 French Open boys' singles title, Kližan turned pro in 2007 and had a career-high singles ranking of world No. 24, achieved on 27 April 2015, and world No. 73 in doubles, achieved on 4 May 2015.
Career
Junior career
In 2005, he won the European Junior Championship in the under-16 category, in both singles and doubles. In doubles, his partner was compatriot Andrej Martin. Kližan then went on to win the 2006 French Open boys' singles competition.
As a junior, Kližan posted a 54–21 win–loss record in singles and 58–18 in doubles. He reached the boys' No. 1 combined world ranking on 1 January 2007.
2010–11: Top 100 debut
In 2010, Kližan qualified for the US Open. In his first main-draw Grand Slam tournament appearance, he lost to former world No. 1 Juan Carlos Ferrero in the first round. Later in the year, Kližan won his first Challenger tournament as a wildcard in his hometown of Bratislava at the Slovak Open. He would subsequently break into the top 100 in September of the following year.
2012: Best Grand Slam fourth round run, Top 30 debut
In 2012, Kližan made it to five Challenger tour finals, winning four, in the space of just two months between March and May. He made it to the second round of a Grand Slam for the first time in his career at the 2012 French Open, before succumbing to Nicolas Mahut in four sets, despite taking the first. These results propelled him into the top 100 of the rankings for the first time in his career. He also reached the semifinals in Kitzbühel. In his Wimbledon debut, he defeated Juan Ignacio Chela 11–9 in the fifth set in the first round, before losing in five sets to Viktor Troicki in the second round, despite being 2–1 up in sets. He competed in men's singles at the 2012 Summer Olympics, as well as the men's doubles with Lukáš Lacko.
At the 2012 US Open, Kližan advanced to the fourth round of a Grand Slam for the first time in his career, upsetting fifth seeded Jo-Wilfried Tsonga in the second round in four sets. Prior to the upset, Klizan had never beaten a player ranked higher than 49th on the ATP Tour. He beat Jérémy Chardy in straight sets to reach the fourth round, where he lost to Marin Čilić. He then won two respective Davis Cup matches against João Sousa and Gastão Elias in a tie against Portugal.
Kližan continued his good form two weeks after the US Open by winning his first ATP tournament, beating Fabio Fognini in the final of the 2012 St. Petersburg Open. Due to this result, he finished the year as World No. 30 after having finished the previous year as World No. 117.
2013: Loss of form
Coming into 2013, Kližan was expected to reach at least the top 20. However, with his inconsistent nature, Kližan alternated good results with very bad ones. After first-round losses at the start of the season, he reached the quarterfinals in Rotterdam. Due to this result, he reached his career-high singles ranking of World No. 26.
He went on with poor results until the semifinals in Casablanca. At the 2013 French Open, he lost in the second round against eventual champion Rafael Nadal, despite winning the first set. Subsequently, he participated in a Challenger tournament in Caltanissetta, Italy, where Kližan suffered a shocking loss to non-ranked player Pablo Carreño Busta in the first round. Afterwards, Klizan returned to the main tour and after reaching the quarterfinals in Umag and winning his first-round match in Montreal against Thomaz Bellucci, lost in the first round of every tournament, peaking at the 2013 US Open, where he lost to Donald Young. He did not play for six weeks due to a wrist injury and withdrew from St. Petersburg, where he was the defending champion.
2014: Return to form, First Australian and French Open third rounds
Kližan started the year with a first-round loss at the Nouméa, New Caledonia Challenger tournament to World No. 258 Kimmer Coppejans. After a poor start of the year, he found very good subsequent form at the Australian Open. Starting from qualifying, his achieved his best result in Australia by reaching the third round as a lucky loser, where he lost to another lucky loser: Stéphane Robert.
He continued his good form at the 500 tournament in Rio. Starting again from qualifying, he reached the second round. This result saw Kližan return to the top 100 of the rankings at World No. 97. In São Paulo, Kližan reached the quarterfinals, where he lost to semifinalist Thomaz Bellucci.