Zabaleta got the upper hand in an exciting and unpredictable match. He has beaten Rios in their last four meetings.
The unseeded Argentine player stormed into a 3-0 lead in the first set. At this point Rios began to produce some of the quality shots that carryied him to the top of the world rankings in 1999.
Returning Zabaletas service with venom, the Chilean fought his way back to 5-5. The set went to a tie-break, but Zabaleta edged it 7-4.
Rios upped the pressure and took the second set in just 24 minutes.
The final set was finely balanced until Zabaleta broke Rios serve to go to 4-2. Concluding the set 6-3, Zabaleta celebrated by donning the number 10 shirt worn by Argentine soccer star Diego Maradona.
Zabaleta will meet fellow Argentine Agustn Calleri in the quarter-finals. Calleri beat Brazils Fernando Meligeni 5-7 6-3 6-3 also on Thursday.
In the days other matches, home player Jose Acasuso beat Italys Andrea Gaudenzi 6-4 6-4 and Feliciano Lopez beat fellow Spaniard Felix Mantilla 6-3 3-6 6-3.
Acasuso lost to Brazils Gustavo Kuerten in the final of the 2001 Buenos Aires Open, and he looked on winning form against Gaudenzi.
MEMPHIS (Tennessee): Andy Roddick showed just why he is fast becoming one of the hottest properties in men’s tennis after completing a remarkable comeback against Andre Sa to reach the quarterfinals of the Kroger St. Jude in Memphis.
After trailing by a set and 4-0, the second seed won six games in a row to level matters before taking the match 5-7 6-4 6-3 to book a quarter-final clash with Armenia’s Sargis Sargsian.
In the women’s draw Americans Lisa Raymond and Alexandra Stevenson were among Thursday’s quarter-final winners.
The second-seeded Raymond got past fellow American Jill Craybas 6-4 6-4, while the fourth-seeded Stevenson overcame Croatian Silvija Talaja 6-1 4-6 6-2.
Roddick, who lost to Tommy Haas at the quarter-final stage last year after losing his cool mid-way through the match, acknowledged that things are a little different for him these days.
Third seed Jan-Michael Gambill also had to recover from a set down to defeat fellow American Paul Goldstein 4-6 6-2 6-0.
Women’s third seed Ai Sugiyama of Japan and unseeded Russian Alina Jidkova also advanced.
Sugiyama beat fifth-seeded Italian Adriana Serra-Zanetti, 6-0 6-4, while Jidkova dismissed Canadian Jana Nejedly 7-6 6-2 at the Racquet Club of Memphis.
Friday’s semis will pit Raymond against Sugiyama and Stevenson versus Jidkova.
All four semifinalists are seeking their first title of the year.
Stevenson and Jidkova have never won a title on the WTA circuit.—Reuters