Rio de Janeiro - After 52 straight semi-final clay court wins stretching back 12 years, top seeded titleholder Rafael Nadal saw his streak end on Saturday, exiting the Rio Open to Italian Fabio Fognini.
Fognini, who had lost his four previous meetings with the 14-time grand slam champion, won 1-6, 6-2, 7-5 to reach a Sunday final against Spaniard David Ferrer.
Second seed Ferrer reached the trophy match with a 7-5, 6-1 win over Austrian Andreas Haider-Maurer.
"I played well in the first set but lacked tactical and physical continuity thereafter," said Nadal.
"It was very humid out there and I got tired much quicker than normal. I started cramping as well - which is very unusual for me," said the Spanish star.
Nadal, who only came off court at 03:30 after Friday night's quarter-final win over Uruguayan Pablo Cuevas, was visibly fatigued, allowing his early momentum to slip as he crashed out after 2 hours 17 minutes.
"I am very pleased as I played the best in the world on this surface. This is my best career win to date," said 28th-ranked Fognini, seeded four at the event whose inaugural edition Nadal won last year.
That success was a building block early in a clay season which would culminate in a ninth Roland Garros title, but a series of injuries thereafter hampered Nadal.
The Mallorcan came to Brazil on the back of a poor start to the year after a first round exit in Qatar and a quarter-final loss at the Australian Open.
Nadal was furious after he was forced into a late night start Friday with all four quarter-finals played on center court and all going the distance.
Fognini's last eight meeting with Argentine Federico Delbonis lasted more than three hours before the Australian Open doubles champion alongside compatriot Simone Bolelli emerged a 6-4, 6-7, 7-6 winner.
It was the Italian's fatigue which showed early on as Nadal blitzed him in the opening set. An early break in the second looked as if the titleholder would emerge victorious.
Instead, a double fault allowed Fognini a toe hold. He threw that one away in missing a simple volley but thereafter the momentum swung inexorably his way with a trio of breaks seeing the Italian level matters.
Nadal tried to dig his way out of trouble in the decider as, trying to avoid a first loss in 21 matches in Brazil, he began to run out of juice as Fognini took the honors on his third match point.
After pushing Nadal deep, he saw the Spaniard's weak backhand return clip the tape and the Italian just made up the ground as he just managed to reach a low, stabbed volley to complete the win.
Next week's ATP event in Buenos Aires will offer a chance of some redemption as Nadal looks to find his top form in time for more glory in France come early June.
Ferrer twice dropped serve against Haider-Maurer in a tight opener on center court at the swish Rio Jockey Club but the Spaniard moved through the gears to break in the 11th game and then motored through the second set.
Ferrer is 7-0 against Fognini in previous meetings ahead of the final.
The women's final will pitch 16th-ranked Italian Sara Errani, the top seed, against 75th-ranked Slovak Anna Schmiedlova on Sunday.
Errani came past fifth-seeded Swede Johanna Larsson 7-5, 6-3 while sixth seed Schmiedlova shocked second-seeded Romanian hope Irina Begu 6-3, 4-6, 6-2.