Question: What sport did Robert Lindstedt and Alex O'Brien play?

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2009 Legg Mason Tennis Classic – Doubles: Marc Gicquel and Robert Lindstedt were the defending champions, but Gicquel chose not to participate that year. <BR>Robert Lindstedt partnered with Martin Damm, and won in the final over Mariusz Fyrstenberg and Marcin Matkowski, 7–5, 7–6.

2014 ABN AMRO World Tennis Tournament – Doubles: Robert Lindstedt and Nenad Zimonjić were the defending champions but decided not to participate together.  Lindstedt played alongside Łukasz Kubot, but lost in the first round to Julien Benneteau and Édouard Roger-Vasselin.  Zimonjić teamed up with Daniel Nestor, but lost in the quarterfinals to Michaël Llodra and Nicolas Mahut.

2015 Australian Open – Men's Doubles: Łukasz Kubot and Robert Lindstedt were the defending champions, but chose not to participate together.  Kubot teamed up with Jérémy Chardy, but lost in the second round to Alex Bolt and Andrew Whittington.  Lindstedt played alongside Marcin Matkowski, but lost in the second round to Jonathan Erlich and Treat Huey.

2016 Winston-Salem Open – Doubles: Dominic Inglot and Robert Lindstedt were the defending champions, but chose not to participate together.  Inglot played alongside Marin Draganja, but lost in the quarterfinals to Lindstedt and Aisam-ul-Haq Qureshi.  Lindstedt and Qureshi then lost in the semifinals to Andre Begemann and Leander Paes.

2013 Topshelf Open – Men's Doubles: Robert Lindstedt and Horia Tecău were the defending champions but Lindstedt decided not to participate. <br>

Robert Lindstedt: Robert Lindstedt (born 19 March 1977) is a Swedish professional tennis player, who turned pro in 1998, and is a doubles specialist.  His biggest title has been the 2014 Australian Open with partner Łukasz Kubot.  He is also a three-time Wimbledon finalist with former partner Horia Tecău.

2011 Winston-Salem Open – Doubles: Robert Lindstedt and Horia Tecău were the defending champions, but Lindstedt chose not to participate.

2010 Pilot Pen Tennis – Men's Doubles: Julian Knowle and Jürgen Melzer were the defending champions, but Melzer chose not to participate this year.As a result, Knowle partnered with Andy Ram, but they lost to Robert Lindstedt and Horia Tecău in the semifinals.  Lindstedt and Tecău went on to win the tournament, after defeating Rohan Bopanna and Aisam-ul-Haq Qureshi in the final 6–4, 7–5.

Alex O'Brien: Alex O'Brien (born March 7, 1970 in Amarillo, Texas) is a retired professional tennis player from the United States, who competed on the ATP Tour.  He became the world No. 1 doubles player in May 2000 and was ranked as high as world No. 30 in singles in June 1997.

2010 UNICEF Open – Men's Doubles: Wesley Moodie and Dick Norman were defending champions, but they lost in the semifinals against Robert Lindstedt and Horia Tecău. Lindstedt and Tecău won the final 1–6, 7–5, [10–7] against Lukáš Dlouhý and Leander Paes.

Supporting paragraphs: Robert Lindstedt Alex O'Brien
Answer: tennis