Top seed Andy Roddick suffered a surprise defeat at the Rome Masters, as Fernando Verdasco advanced to the last eight with a 6-7 7-6 6-4 success.
Roddick had three match points when 5-3 up in the second set, but though a double fault was called against Verdasco, the American corrected it.
Verdasco broke and smashed two huge backhands to win the tie-break.
He broke in the first game of the final set to win in two hours 32 minutes and will now face Guillermo Coria.
The ninth seed surged through with a 6-0 6-4 win over home favourite Davide Sanguinetti.
Wildcard Sanguinetti, ranked 76th in the world, looked well out of his depth against clay court specialist Coria.
The Argentine said: "I feel I'm getting better and better. It's the first time I've got as far as the quarters here."
Sanguinetti's initial tactic of playing from the baseline proved badly flawed as his opponent used his metronomic groundstrokes to wrap up the first set in 30 minutes.
The Italian then held serve in the first game of the second, but a pair of unforced errors in the third gave world number 11 Coria the break he needed to close out the contest with ease.
Rafael Nadal is also through to the quarter-finals as he extended his winning streak to 14 matches by beating Guillermo Canas 6-3 6-1.
"I had to raise the level of my game for my toughest match so
far and I am very satisfied with the result," said Nadal, who hit 26
The Spanish teenager, bidding for his fifth singles title of the year, is now the highest placed seed left in the tournament.
He now plays Czech Radek Stepanek, who beat Nicolas Almagro.