Lu Yen-hsun of Taiwan reached his first ATP tour final with shock 6-4 7-6 victory over David Ferrer at the Heineken Open in Auckland.
Unseeded Lu ended the Spaniard's bid for a fifth title at the New Zealand venue and a fourth in succession, as the top seed dropped serve twice in the opening set.
Lu showed virtually no sign of nerves playing in his first semi-final since joining the ATP tour in 2001, while the normally unflappable Ferrer yelled at himself in frustration as the match slipped away.
"I know he's a tough guy and I tried to play my best tennis and fortunately I did it," Lu said. "He's not playing bad, I just played unbelievable."
Ferrer is seeded third for the Australian Open starting on Monday.
Lu will take on big-serving American John Isner in the final after the 2010 champion overcame unseeded Spaniard Roberto Bautista Agut 3-6 7-6 6-4.
The world number 14 went into the match carrying an ankle injury and Bautista Agut moved him around the court from the start, reaping immediate rewards with a service break in the second game.
He held onto the advantage and served out the set at after 30 minutes, Isner not helping his cause with 17 unforced errors as he struggled to find his rhythm.
The next set appeared to be following a similar pattern, with Bautista Agut comfortably handling the lanky American's much-vaunted serve and going up a break in the first game.
But Isner levelled at 5-5, took the subsequent tie-break 7-2 before closing out the deciding set.
"I got a little bit fortunate at 5-4 in the second set, it sort of turned the match around and I grabbed the momentum and went on from there," he said.