Australian qualifier Peter Luczak pushed second seed Juan Monaco to three sets before bowing out in the quarter-finals of the Movistar Open in Santiago.
Three breaks were enough for the Argentinean to win the near two-hour clash 6-4 3-6 6-3.
Top seed Fernando Gonzalez came through two lengthy tie-breakers against Marcel Granollers to reach the semi-finals, the hometown player triumphing after a topsy-turvy two-and-a-quarter hours which saw each player break serve three times.
Four of those six breaks came in the first set, which Gonzalez took 10-8 in the breaker - and the second was even more closely fought, the Chilean holding his nerve once more to complete a 7-6 (10-8) 7-6 (11-9) win.
He will play third seed Thomaz Bellucci, who came through his clash with Argentina's Eduardo Schwank in much more comfortable fashion.
The Brazilian broke twice and did not face a single break point himself as he won 6-4 6-4 in one hour and 17 minutes.
Monaco will face Joao Souza in the last four after he hammered Spain's Alberto Martin 6-2 6-4.
Meanwhile, top seed Gael Monfils will meet Feliciano Lopez in the first semi-final of the SA Tennis Open in Johannesburg, while David Ferrer set up a last-four clash against Stephane Robert at Montecasino.
Frenchman Monfils, the world No.13, had little trouble against the eighth seed Lu Yen-Hsun, who turned in an error-strewn performance on his way to a 6-1 6-4 loss.
The Chinese Taipei player won just one game in the first set - 16 unforced errors not helping his cause - before a much better display in the second set came too late as one break was enough to take the two-time ATP Tour winner to victory.
Monfils will now meet No.3 Lopez for a place in Sunday's final after the Spaniard beat Rajeev Ram.
The American had several chances to take the game to his opponent, squandering seven break points before falling 7-6 (7-2) 6-3.
In the bottom half of the draw, second seed Ferrer dropped just four games on his way to a crushing 6-1 6-3 win over Somdev Devvarman.
The Spaniard, who also reached the semi-final in the same competition last year, wasted little time against the Indian with his strong first serve carrying him a long way - the world No.18 won 20 out of 25 points to ease home in 66 minutes.
Ferrer will play Robert in the last four after the Frenchman came through a testing 7-6 (7-5) 6-4 win against the feisty Dustin Brown.
Germany-born Brown, who represents Jamaica, had impressed all week following his opening-round win against fourth seed Marco Chiudinelli and again threatened to cause another upset.
But after taking his opponent to a tie-breaker he narrowly lost out, before throwing away six break point opportunities in the second set to hand Robert victory.
In Croatia, reigning champion and top seed Marin Cilic reached the semi-finals of the PBZ Zagreb Indoors with a hard-fought 7-6 (8-6) 6-4 victory over fellow Croatian Ivo Karlovic.
Cilic, who is currently a career-high No.10 in the world rankings, failed to take advantage of the four break points he managed to force in the first set as it went to a tie-breaker.
But the 21-year-old, on the back of his semi-final appearance at the Australian Open, came through to take the tie-breaker 8-6 to go a set up.
He then completed his victory as he claimed the only break