Nicolas Almagro's hopes of winning a third straight Brazil Open title ended in the quarterfinals on Friday when he lost 7-6 (5), 3-6, 7-6 (3) to David Nalbandian.
The second-seeded Spaniard, 11th in the world, played well but failed to capitalize on his opportunities against the 93rd-ranked Nalbandian. He had 11 break chances but converted only two of them, while the Argentine took advantage of one of his four break points.
Almagro had 28 aces against five for Nalbandian, but it was not enough as the Argentine played better in both tiebreakers to win the indoor clay-court match in 2 hours, 17 minutes.
The 31-year-old Nalbandian, who was No. 3 in the world in 2006, is making his season debut in singles at the Brazil Open. He withdrew from the doubles tournament earlier in the week because teammate Rafael Nadal decided to rest his injured left knee.
Almagro was looking for his fourth title in Brazil, having also won the tournament in 2008. This was his first event since his five-set loss to compatriot David Ferrer in the Australian Open quarterfinals in January.
Nalbandian will now play Simone Bolelli of Italy, who reached his first ATP semifinals since 2008 when he defeated Albert Montanes of Spain 6-4, 6-4.
The 80th-ranked Bolelli, who successfully played challengers last year to get back into the top 100, broke Montanes' service twice in the final set to secure the victory at the indoor clay-court tournament in Sao Paulo.
The Italian converted three of his 11 break point opportunities and had five of his nine aces in the second set at the Ibirapuera arena.
Bolelli upset third-seeded Juan Monaco of Argentina in the second round on Thursday.
Argentine Martin Alund, No. 111 in the world, beat 88th-ranked Filippo Volandri of Italy 7-5, 7-6 (5) to set up a likely encounter with top-seeded Nadal, who was to face Carlos Berlocq of Argentina in Friday's last match.
The 27-year-old Alund had never won a match at the top tour level until he came to Sao Paulo. He had beaten 25th-ranked and fourth-seeded Jeremy Chardy of France in the second round.
The Brazil Open was played in the northeast coastal city of Costa do Sauipe from 2001-2011, moving to Sao Paulo for the first time last year.