Houston, April 14:

Fourth-seeded Marcos Baghdatis of Cyprus retired in his second-round match against American Vince Spadea on Thursday because of lower back pain.

The unseeded Spadea was ahead 6-2, 3-1 when Baghdatis walked to the sideline favouring his right leg after being broken for the third time in the match and told the umpire he could not continue.

Spadea plays Mardy Fish of the United States in the quarter-finals. Fish’s second-round opponent, Rainer Schueltter of Germany, defaulted because of a stomach ailment.

In other second round matches, Albert Montanes of Spain defeated Tomas Behrend of Germany 6-2, 6-3 to reach the quarter-finals, his third this season.

Montanes, who put out third-seeded Robby Ginepri in the first round, will face seventh-seeded Paul Goldstein, who defeated qualifier Scoville Jenkins 6-4, 6-1 in an all-American second-round match. Jurgen Melzer of Austria outlasted Marcos Daniel of Brazil 7-6 (2), 6-4.

Family Circle Cup

CHARLESTON: Defending champion Justine Henin-Hardenne extended her unbeaten streak at the Family Circle Cup to 13 matches by defeating Karolina Sprem of Croatia 6-4, 6-4 to reach the quarter-finals.

Henin-Hardenne’s latest win on the green clay took more than 90 minutes on a warm, windy afternoon. Henin-Hardenne faces Dinara Safina of Russia, who won 6-7 (6), 6-2, 6-2 over Julia Vakulenko, a Ukrainian qualifier who knocked off 10th-seeded Jelena Jankovic earlier in the week.

Second-seeded Nadia Petrova put away Lucie Safarova of the Czech Republic 6-1, 6-3, and will take on Catalina Castano of Colombia, who led 5-4 when Marion Bartoli of France retired with an inflamed knee.

No 3-seeded Patty Schnyder of Switzerland turned back Mara Santangelo of Italy 3-6,

7-6 (2), 6-3 and faces Nathalie Dechy of France, who defeated Katarina Srebotnik of Slovakia 6-2, 6-3.

Fourth-seeded Svetlana Kuznetsova of Russia downed Spain’s Lourdes Dominguez Lino 6-2, 6-1 in 57 minutes. In quarters, Kuznetsova, ranked No 10 in the world, meets Anna-Lena Groenefeld of Germany, a 7-6 (3), 6-3 winner over Anabel Medina Garrigues of Spain.