Buenos Aires, Argentina: Guillermo Canas eliminated top-seeded David Nalbandian 6-4, 6-4 from the Copa Telmex round robin on Wednesday.Also, two former French Open champions, Juan Carlos Ferrero and Gaston Gaudio, both lost and needed to win their last group matches on Thursday to reach the last eight. And two former finalists, third-seeded Agustin Calleri and eighth-seeded Jose Acasuso, withdrew injured.Canas said after winning his seventh career title last week in Costa do Sauipe, Brazil that he was determined to win his hometown tournament this week for the first time. He broke his fellow Argentine Nalbandian in the final game of both sets to even their head-to-head at 2-2 in their first clash on clay."I'm just happy to have lived through this moment," unseeded Canas said. "It was just incredible out here on court." Nalbandian double-faulted and committed other unforced errors in losing his serve at 4-5 in the first set.In the second, Canas broke Nalbandian for 5-3 when Nalbandian double-faulted for the second time. However, Nalbandian broke back immediately then stumbled a final time on his next service game. He quickly trailed 15-40, saved one match point with a powerful first serve, but Canas smashed a winning return.On Thursday, Canas will face Luis Horna of Peru, who won the first tournament in this South American clay court swing in Vina del Mar, Chile. Horna on Wednesday upset Nalbandian 6-4, 6-3.Gaudio, the 2005 champ and sixth seed, put in only 48 per cent of his first serves and was broken six times by Ramirez Hidalgo.Devilder beats FerreroSecond-seeded Ferrero was upset by Nicolas Devilder 1-6, 7-6 (2), 6-0 for the Frenchman's best-ever result.Devilder lost to Ferrero 6-2, 6-4 last week in the second round at Costa do Sauipe, and was on course to fall in straight sets again on Wednesday when the former No 1 cruised through the first set. But they broke each other twice in the second set, Devilder dominated the tiebreaker, and in the third set, Devilder snapped up three break chances while Ferrero squandered a trio.Ferrero can still win his three-man group and advance to the quarterfinals if he beats Nicolas Lapentti of Ecuador on Thursday.Calleri, the 2002 runner-up who lost his first group match, withdrew complaining of back trouble, and was replaced in the draw by Czech Jiri Vanek, who lost to Brazil's Flavio Saretta 7-6 (8), 6-7 (2), 6-3.Acasuso, the 2001 runner-up, retired with a right elbow injury after losing the first set 6-3 to unseeded compatriot Diego Hartfield, ending this year's appearance in the hometown tournament in which he's reached the final once and semifinals twice.Elsewhere, sixth-seeded Juan Ignacio Chela of Argentina beat Alberto Martin of Spain 6-1, 6-3 and will decide his group winner with Igor Andreev of Russia; Argentina's Juan Monaco beat Italy's Potito Starace 6-3, 6-4 and will face Carlos Moya for a last-eight berth, and Argentina's Martin Vasallo Arguello downed Italy's Stefano Galvani 6-2, 6-4.