RIO DE JANEIRO (AP) -- Rafael Nadal showed no problems with his tender back as he marked the second match in his return from injury with a 6-1, 6-2 win over fellow Spaniard Albert Montanes to reach the quarterfinals of the Rio Open on Thursday.
The No. 1-ranked Nadal tweaked his back warming up for the Australian Open final, which he lost almost four weeks ago in a major upset against Stanislas Wawrinka.
His first stop after a layoff is the clay courts in Rio as he tests the back and tries to stay healthy for the French Open in three months. A year ago he used the Latin American swing to test his recovery from an injured left knee.
Nadal seemed to move freely against Montanes and wore a large, blue brace on his lower back as a precaution.
Nadal has used the words ''cautious'' to describe his return, and acknowledged he was a ''bit afraid'' as he begins the comeback.
Alexandr Dolgopolov of Ukraine advanced to his second quarterfinals of the year, beating Facundo Bagnis of Argentina 6-7 (4), 6-2, 7-6 (4).
Dolgopolov said he hadn't considered leaving the tournament to return to his Kiev birthplace, where more than 100 people have died in anti-government protests this week. Government snipers killed at least 70 on Thursday.
''It's sad. I can't do much, but just support,'' he said. ''Whoever is right doesn't matter now when people are dying.''
Dolgopolov, who lives in the wealthy European enclave of Monte Carlo, said he was lucky to have the chance to make money playing tennis.
''Obviously I would like the people in the (Ukraine) to feel better. If I could, I would change that,'' he said.
On the women's side of the combined ATP-WTA event, fifth-seeded Kurumi Nara of Japan and Lourdes Dominguez Lino of Spain set up a quarterfinal matchup after second-round wins.
Nara defeated Anna-Lena Friedsam of Germany 6-0, 7-6 (3), and was in sight of her first WTA semifinals. Dominguez Lino beat Chanelle Scheepers of South Africa 2-6, 7-6 (7), 6-1.
Nara said she likes the hot weather in Rio and is getting used to the clay.
''Now I like the clay court,'' she said. ''Last year, I didn't like it.''
Irina-Camelia Begu of Romania also made the last eight, as did Brazil's Teliana Pereira. She is the first Brazilian woman in 23 years to crack the WTA's top 100. The last was Andrea Vieira.
Brazil's most famous women's player is Maria Bueno, who won seven Grand Slams singles titles, the last at the US Open in 1966.
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