Robredo joins compatriots Carlos Moya, Juan Carlos Ferrero and his next opponent, holder Albert Costa, in the last eight.
Tommy Robredo accused Novak Djokovic of exaggerating the seriousness of his injuries to get some extra rest during their draining fourth round at the US Open.
Carlos Moya, Paradorn Srichaphan and Felix Mantilla are the other top players who have already confirmed their entry.
Tommy Robredo suspected he could stun Roger Federer at the US Open because the Swiss master had developed self-doubts, the Spaniard said after the extraordinary upset on Monday.
The Spaniard lost 6-4, 7-6 to France's Marc Gicquel in the first round of the Lyon tournament.
Tommy Robredo demolished fellow Spaniard Feliciano Lopez 6-2, 6-2 at the Barcelona Open.
Rafael Nadal extended his winning streak on clay to 46 after he edged out fellow Spaniard Nicolas Almagro at the Barcelona Open.
top seed Tommy Robredo lost his opening match at the Swedish Open on Monday to Peruvian Luis Horna.
The French Open champion overcame a mid-match slump to defeat Spaniard Tommy Robredo 6-1, 2-6, 6-1 in the final.
Rafael Nadal kept winning the hard way at the Paris Masters on Thursday, overcoming fellow Spaniard Tommy Robredo 6-3, 3-6, 7-5 to reach the quarter-finals. Nadal, who saved five match points before taming Nicolas Almagro in another all-Spanish battle on Wednesday, needed two hours and 20 minutes to shrug off a brave challenge from Robredo, seeded 14th in the indoor event.
Defending champion Novak Djokovic breezed past misfiring Spaniard Tommy Robredo 6-1, 6-1 to reach the Rome Masters quarter-finals on Thursday. World number two Roger Federer had to work only slightly harder to progress with a 6-4, 6-1 win over 16th seed Radek Stepanek and avenge the quarter-final defeat he suffered against the Czech here last year.
Croatian Ivan Ljubicic grabbed the last ticket to the eight-strong Masters Cup on Friday.
Gaudio beat Guillermo Garcia-Lopez in a three set semi-final at the Estoril Open while Robredo advanced after Carlos Moya retired.
Roddick defeated Tommy Robredo while Srichapan ended the run of 17-year-old Rafael Nadal.
Ivan Ljubicic reached his second final in two weeks when he beat fifth-seeded Spaniard Tommy Robredo.
Making an astonishing comeback from the brink of defeat, defending champion Paradorn Srichaphan of Thailand pipped fourth seed Spaniard Tommy Robredo 1-6, 7-6, 7-5.
Amitabh and Abhishek watch Fedex -- also known as the Greatest Tennis Player currently on the planet -- defeat Spaniard Tommy Robredo in the quarter-final and enter the semi-final of the Grand Slam event.
The French Open champion will open his 2006 season at the Chennai Open starting on January 2.
Roger Federer beat Russian Mikhail Youzhny at the Dubai Open on Saturday.
France's Richard Gasquet ended Andy Murray's Masters Cup hopes by beating the British number one 6-3, 0-6, 6-4 in the Paris Masters Series quarter-finals on Friday.
James Blake beat Russia's Nikolay Davydenko 2-6, 6-4, 7-5 in the Shanghai Masters.
Andy Roddick and Juan Carlos Ferrero will contest the Cincinnati Masters final on Sunday.
The world No. 1 was twice made to come from behind for his 55th consecutive win on North American hardcourts, in the Cincinnati Masters.
Rafael Nadal cruised into the Swedish Open final with a 6-3, 6-3 victory over fellow Spaniard Tommy Robredo.
Argentine fifth seed Juan Martin del Potro overcame a bout of jitters to stroll into his first grand slam semi-final with a 6-3 6-4 6-2 win over Spaniard Tommy Robredo at the French Open on Wednesday.
Delhi Dreams stormed into the final of the inaugural Champions Tennis League by overcoming a spirited Mumbai Tennis Masters by 27-21 in the best-of-five one-set clashes here at the Kalina University sports complex courts on Sunday night.
Only Frenchman Richard Gasquet stands in the way of a Spaniard appearing in next Monday's men's final after Rafa Nadal, Tommy Robredo and David Ferrer all sailed into the quarter-finals.
Rafael Nadal steamrolled compatriot Tommy Robredo 6-0, 6-2, 6-2 to move into the semi-finals of the US Open at Flushing Meadows on Wednesday.
Tommy Robredo proved size is not everything in tennis, cutting towering American John Isner down to size to give Spain a 3-0 victory in their opening Hopman Cup encounter on Sunday.
Leander Paes and his partner Lukas Dlouhy entered the quarterfinals of the euro 2,750,000 Monte-Carlo Rolex Masters in Monaco, defeating unseeded Spaniard duo of Albert Montanes and Tommy Robredo in a match tie-breaker.
World No 2 Rafael Nadal recovered from a slow start to beat compatriot Tommy Robredo and get his Masters Cup campaign back on track.
Tommy Robredo was the driving force as Spain came from behind to beat Britain 2-1 on Saturday to win the Hopman Cup for a third time.
Tim Henman and Juan Carlos Ferrero slumped to demoralising defeats in the second round.
Leander Paes and his partner Lukas Dlouhy breezed past Spaniards Nicolas Almagro and Tommy Robredo to storm into the Sony Ericsson Open doubles final in Miami.