Berlocq started playing tennis at the age of four and had success on the
ATP Futures and Challenger circuits. In 2004, he made six consecutive finals on the Futures circuit and won half of them, two each in
Argentina,
France and
Slovenia. He also made his first Challenger final in
Manta, Ecuador, losing to
Giovanni Lapentti before winning another Futures title in Argentina. At the end of 2005, Berlocq finished inside the top 100 for the first time on the back of strong form on the
Challenger Tour, where he went 44–20 in singles and won two titles in
Turin (defeating
Alessio di Mauro) and in
Cordenons (defeating
Jérôme Haehnel). Berlocq also qualified for his first ATP main event in
Stuttgart, losing to
Răzvan Sabău. He also played doubles in
Bucharest with
Mariano Puerta. Berlocq struggled to adapt his level from the Futures and Challengers to the ATP main level events and achieved only limited success on the
ATP Tour. However, his first win was significant. At the
ATP Masters Series event in
Miami, Berlocq defeated the much-hyped
American junior and wildcard entrant
Donald Young 6–0, 6–0. Neither player had won a match on the ATP Tour and this win was achieved on a
hardcourt, not Berlocq's favoured surface. After defeating Young, Berlocq played another American,
James Blake, losing this match 0–6, 0–6 and therefore creating an unusual achievement of winning his first ATP-level match 6–0, 6–0 and then losing by the same scoreline in the next round. Berlocq won two consecutive matches for the first time on the ATP Tour to make the quarterfinals in
Sopot after defeating
Philipp Kohlschreiber and
Lukáš Dlouhý. On May 29, 2007, Berlocq upset the No. 30 seed
Julien Benneteau in four sets 6–7(5–7), 7–5, 6–2, 6–3 at the
2007 French Open. Berlocq won his first ever
grass court match in
's-Hertogenbosch against former World No. 1
Juan Carlos Ferrero in three sets.
2011 At the
French Open, he defeated Australian
Bernard Tomic 7–5, 6–4, 6–2 in the first round. Berlocq was taken out by World No. 1
Novak Djokovic in three sets 6–0, 6–0, 6–2 in the second round of the
2011 US Open.
2012 Berlocq started the year in
Auckland, losing in the second round to
Fernando Verdasco. He made it to the second round of the
2012 Australian Open, where he was defeated by
Ivo Karlović. His best result of the year was in
Viña del Mar, where he defeated World No. 25
Juan Ignacio Chela in the semifinals to set up a final appearance against
Juan Mónaco, which he lost. He made the quarterfinals in
São Paulo,
Buenos Aires and
Acapulco, losing to World No. 11
Nicolás Almagro,
David Nalbandian and
Santiago Giraldo respectively. He also made the quarterfinals in
Houston, exiting against World No. 15
Feliciano López. He did not have much success at the
Masters 1000 events or
Grand Slams, exiting in the first or second round of each. In
Umag, he fell to World No. 19
Alexandr Dolgopolov in the quarterfinals. He represented Argentina at the
2012 Summer Olympics, but lost in the first round to
Alex Bogomolov of
Russia. At the
US Open, he was defeated in the first round by Bernard Tomic in four sets.
2013 He beat
Maxime Authom 1–6, 7–6(7–5), 7–6(7–4), 6–2 in the first round of the
Australian Open before losing to
Kei Nishikori 6–7(4–7), 4–6, 1–6. He lost his first round match at the French Open against 19th seed
John Isner in straight sets. Berlocq won his first career title at the
Swedish Open, defeating Fernando Verdasco in the final. He lost in the second round of the
US Open in straight sets to
Roger Federer after winning his first round match against Santiago Giraldo in five sets.
2014 In April, Berlocq won the
Portugal Open after defeating
Tomáš Berdych in the final. ==ATP career finals==