Until 2006, Diego Hartfield only played futures and challenger tournaments. In 2006 he made his international breakthrough. In Atlanta he won his first Challenger title against Frank Dancevic and a week later he won the final against Mardy Fish at the Challenger tournament in Tunica Resorts . At the ATP tournament in Stuttgart he reached the third round after defeating Nicolás Almagro . The Argentine made his Grand Slam debut at the French Open , where after a good performance he was defeated by world number one Roger Federer 5: 7, 6: 7 and 2: 6.
Diego Hartfield had his most successful season in 2007. He achieved his best result in Buenos Aires, where he was able to reach the semi-finals of an ATP tournament for the first time. In Houston he defeated the former top ten player Sébastien Grosjean and was close to the French Open in Pörtschach after victories over Stanislas Wawrinka and Vincent Spadea in the quarterfinals, which he lost to Lleyton Hewitt . In Paris he was eliminated in the second round against David Ferrer . In July he moved into the third round in Kitzbühel and at the end of the year the clay court specialist surprisingly reached the quarter-finals of the indoor tournament in Lyon . In the world rankings, he improved to number 73.
In 2008 the Argentine fell far behind. At the beginning of the year he had absolutely no chance at the Australian Open in round one against Roger Federer at 0: 6, 3: 6, 0: 6. His biggest success of the season was a win over Tommy Haas in Delray Beach .
Argentina
Atlanta
Frank Dancevic
Bogotá III
Daniel Köllerer
Frederico Gil Dick Norman
Bordeaux
Tomasz Bednarek Dušan Vemić