Brydan Klein went down 7-6 6-3 to 19-year old Mathias Bourgue at the qualifiers for the French Open in Roland Garros.
Argentina face Germany in the Davis Cup this weekend on shakier ground at home than when they beat their opponents last year.
Holders Spain will take on the Czech Republic in their fourth Davis Cup final in five years after both nations won their respective semis.
Czech Republic's path to the Davis Cup final was wide open after they won the doubles and Argentine Juan Martin del Potro pulled out.
With Andy Roddick retired and Mardy Fish unavailable, the giant John Isner is the main US hope for their Davis Cup clash with Spain.
Juan Martin del Potro will play for Argentina in their Davis Cup semi-final at home to Czech Republic this weekend despite a wrist problem.
Juan Martin del Potro is in doubt with a left wrist problem for Argentina's Davis Cup tennis semi-final at home to Czech Republic.
David Ferrer will lead holders Spain in their Davis Cup semi-final at home to the United States, captain Alex Corretja has said.
Benoit Paire (France) beat Eduardo Schwank (Argentina) 7-6(5) 6-4 Jeremy Chardy (France) beat Julian Reister (Germany) 6-2 6-4
Third round: 20-Marcel Granollers (Spa) bt Paul-Henri Mathieu (Fra) 6-4 6-4 1-6 4-6 6-1
Rafael Nadal continued his untroubled progress towards a seventh French Open title with a 6-1 6-3 6-4 defeat of Eduardo Schwank.
Round-up: Rafael Nadal continued his march towards a seventh French Open title with a demolition of Uzbekistan's Denis Istomin.
Second round: Eduardo Schwank (Argentina) beat 32-Florian Mayer (Germany) 2-6 6-3 6-4 7-6(4); 12-Nicolas Almagro (Spain) beat Marcos Baghda
Rafa Nadal, chasing a record seventh French Open title, will be looking to preserve his perfect record against Uzbekistan's Denis Istomin.
Jarkko Nieminen (Finland) beat Igor Andreev (Russia) 3-6 6-2 2-1 (Andreev retired)
ATP World Tour Finals
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