Rio de Janeiro, Feb 20 (IANS): Spain's Rafael Nadal advanced to the quarterfinals of the Rio Open tennis tournament with a 7-5, 6-3 victory over compatriot Pablo Carreno Busta.

The 14-time Grand Slam winner struggled to assert himself early before breaking Carreno Busta in the 12th game to take the first set Thursday, reports Xinhua.

The world No.3 then broke Carreno Busta's serve in the eighth game of the second set before serving out the match.

Nadal paid tribute to his 209th-ranked countryman in the stifling heat.

"Tough conditions, a difficult, young opponent and I'm just content to be in the quarterfinals," Nadal said.

"For me every victory is important and even more so on clay."

Nadal will Friday meet 52nd-ranked Pablo Cuevas of Uruguay for a place in the semifinals.

Cuevas earlier defeated Albert Montanes of Spain 6-2, 6-2 while Argentine Federico Delbonis beat Martin Klizan of Slovakia 6-2, 6-1.

In the women's draw, Slovakia's Anna Schmiedlova progressed to the last eight with a 6-0, 6-2 win over Argentine Paula Ormaechea.