Updated: Thursday, 10 April 2014 15:32 | By Agence France-Presse

Germany's Brown ousts top seed Isner at ATP Houston

Germany's Dustin Brown upset top seeded American John Isner in three sets to reach the quarter-finals of the US men's clay court championships on Wednesday.

Germany's Brown ousts top seed Isner at ATP Houston

Germany's Dustin Brown, pictured the 2013 Wimbledon Championships tournament at the All England Club in Wimbledon, southwest London, on June 26, 2013 - by Adrian Dennis

The world number 101 Brown outlasted the hard-hitting defending champ Isner 6-4, 6-7 (7/9), 7-6 (7/4) on the clay courts at the River Oaks Country Club.

Isner forced a deciding set by winning an extended tiebreaker in the second, but Brown rebounded to claim the final tiebreak. It was his first-ever victory over a top-10 opponent.

Isner, who is ranked ninth in the world, beat Nicolas Almargo in the 2013 final.

Brown will next face Sam Querrey in the quarter-finals after the 2010 Houston finalist toppled former champ Lleyton Hewitt of Australia earlier on Wednesday.

Querrey beat seventh-seeded former world number one Hewitt 6-3, 6-4 in just 76 minutes. Hewitt, who is enjoying a resurgence this year, won in Houston back in 2009.

In opening-round play on Wednesday, Argentine Juan Monaco stopped India's Somdev Devvarman 7-6 (7/4), 6-2 and Colombian Santiago Giraldo ousted Aussie Matthew Ebden 6-1, 6-2. Monaco titled here two years ago.

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