Juan Ignacio Chela will face David Nalbandian in the semi-finals of the Copa Telmex after advancing from the last eight on Friday.

Unseeded Jose Acasuso also progressed to give Argentina three representatives in the last four of the USD466,000 claycourt event.

Fourth seed Chela progressed at the expense of fifth seed Nicolas Almagro, who retired with a groin injury after trailing 6-3 2-1.

The 28-year-old will meet world number 11 Nalbandian, who claimed a hard-fought 4-6 7-6 (7/5) 6-4 triumph over seventh-seeded Italian Potito Starace, who was participating in his second tournament since serving a six-week ATP-imposed suspension for betting on tennis matches.

It was the second straight difficult match for the top-seeded Nalbandian, who escaped with a 7-6 (7/5) 4-6 6-3 victory over Italian Fabio Fognini on Wednesday.

Acasuso, who eliminated Carlos Moya in the opening round, triumphed over sixth seed Igor Andreev 3-6 6-1 6-3.

It marked the fourth time in five meetings that Acasuso has topped the Russian.

The 25-year-old, a finalist here in 2001, will meet eighth-seeded Italian Filippo Volandri, who prevented an all-Argentinian semi-final line-up with a 6-4 6-4 win over Agustin Calleri.

Bidding for his first ATP final since September 2006, Volandri has lost all five previous meetings with Acasuso.