Horacio Zeballos

Zeballos competed primarily on the ATP Challenger Tour, where he won five singles titles and six doubles titles.

He reached his first ATP Tour final at the St. Petersburg Open, defeating Yuri Schukin, Oleksandr Dolgopolov Jr., Ernests Gulbis and Igor Kunitsyn before falling in the final to Stakhovsky in a third-set tiebreak.

Zeballos started the singles season in a slump, falling in the first round four times, but had an excellent start to the doubles season. In his first tournament, the Heineken Open, Zeballos and Rogier Wassen defeated the world No. 1 team Bob and Mike Bryan. Zeballos then reached the round of 16 at the Australian Open with countryman Leonardo Mayer and reached the final at the Movistar Open with Italian Potito Starace. Zeballos then turned to the clay in the Copa Telmex in Argentina, where in the first round, he defeated countryman and former French Open champion Gastón Gaudio. It was Zeballos' first ATP singles win since he reached the final in St. Petersburg. Zeballos next defeated former world No. 1 Carlos Moyá and reached his first ATP quarterfinal since October, where he then lost to countryman Juan Mónaco. In doubles, Zeballos and countryman Sebastián Prieto were the fourth seed and won the title against Simon Greul and Peter Luczak. It was Zeballos' first career ATP title. The following week, at the Abierto Mexicano Telcel, Zeballos lost in the first round to Łukasz Kubot. He made it to the doubles semifinals with partner Mónaco.

Zeballos was selected for the Argentine Davis Cup team for the first time. He played doubles with David Nalbandian against the Swedish pair of Robert Lindstedt and Robin Söderling. They won in straight sets. Zeballos reached a career milestone as he defeated his first-ever top-25 player, 24th ranked Gilles Simon, in the second round at the Sony Ericsson Open. He then lost in the third round to the eventual finalist Tomáš Berdych.

At the US Men's Clay Court Championships, he defeated Taylor Dent, Dudi Sela, and world No. 11 Fernando González for his first top-15 win and the biggest one of his career. He then faced eventual champion Juan Ignacio Chela in the semifinals, where he lost in straight sets.

At the US Open, Zeballos, with partner Eduardo Schwank, reached the semifinals in doubles.

Zeballos played mostly on the Challenger circuit in singles. He did not make it past the second round in any ATP events. He had more success in doubles, where he won his second title at the 2011 BMW Open partnering Simone Bolelli.

In 2012, he made it to the semifinals in Viña de Mar and Buenos Aires. At Roland Garros, he and partner Oliver Marach made it to the quarterfinals, where they were beaten by the Bryan brothers.

Zeballos won his first ATP singles title at Viña del Mar, where he defeated Rafael Nadal in three sets in his comeback tournament. This victory made Zeballos one of the only four players who have beaten Nadal in a final on clay (the others are Roger Federer, Novak Djokovic and Andy Murray).

He won three doubles titles with Julio Peralta and one with Andrés Molteni.

Zeballos' first match in the 2017 Australian Open was a 5-hour and 15-minute loss to Ivo Karlović, the second longest match by time at the Australian Open in the Open Era.

In June 2017 at Roland Garros, he had his best performance at a major, reaching the fourth round. He was beaten by 6th seed Dominic Thiem in straight sets. At the same tournament, he reached the quarterfinals partnering Julio Peralta.

Zeballos won his first ATP Masters 1000 title at the 2019 BNP Paribas Open with Nikola Mektić. They defeated sixth-seeded Łukasz Kubot and Marcelo Melo in the final. Zeballos became the first ATP Masters doubles champion from Argentina since 1997 after Luis Lobo at the Hamburg Masters.

With his new partner Marcel Granollers, Zeballos won 6 titles starting in August 2019, and also made his first Grand Slam doubles final at the 2019 US Open, losing to the world No. 1 and top seeded pair Farah/Cabal. As a result, he reached a career-high ranking of world No. 3 in doubles on 9 September 2019. The pair won three Masters 1000: the 2019 Canadian Open, the 2020 Italian Open, and the 2021 Mutua Madrid Open. They also reached the 2021 Wimbledon Championships final losing to world No. 1 and top seeds Mektic/Pavic.

In August 2021, they reached a second Masters 1000 final for 2021 and fourth overall at the 2021 Western & Southern Open in Cincinnati, defeating Arévalo/Fognini. They defeated Austin Krajicek and Steve Johnson in the final to win their fourth Masters.

Zebalos and Granollers qualified for their third consecutive ATP finals, having advanced to the semifinals of the year-end championships in 2020 and 2021.

At the 2023 Australian Open Zebalos and Granollers reached back-to-back semifinals.

At the 2023 French Open they upset top seeds Wesley Koolhof and Neal Skupski to reach back-to-back semifinals. They lost to eventual champions Ivan Dodig and Austin Krajicek.

The pair won their first Masters of the season and fifth overall at the 2023 Rolex Shanghai Masters. As a result, he returned to the top 10 on 16 October 2023.

Granollers and Zebalos qualified for their fourth consecutive ATP Finals.

At the 2024 BNP Paribas Open in Indian Wells, Zeballos and Granollers reached the final, saving a match point. At the 2024 Miami Open, they again saved a match point to reach the semifinals.

At the 2024 Monte-Carlo Masters Zeballos and Granollers reached their third Masters semifinal in a row. At the next Masters 1000, the 2024 Mutua Madrid Open, Zeballos and Granollers reached the quarterfinals and both moved into a new career-high ranking of No. 2. With reaching their fourth Masters semifinal of the season, with a win over Hugo Nys and Jan Zielinski, they became joint World No. 1 on 6 May 2024, Zeballos being the first Argentinian man to accomplish the feat. They reached again a Masters final at the Italian Open, and fourth final for the season, defeating the newly formed pair of Alexander Bublik and Ben Shelton. They won their sixth Masters title as a team defeating Marcelo Arévalo and Mate Pavić.

At the 2024 French Open, they reached their third consecutive semifinal at this Major defeating 15th seeds Hugo Nys and Jan Zieliński, and then Tomas Machac and Zhang Zhizhen.

He won his eighth Masters title at the 2024 National Bank Open, second for the year and at this tournament, and tenth as a team with Granollers.