Defending champion David Ferrer crashed out of the Auckland Open semi-finals Friday when Taiwan's Lu Yen-Hsun staged a stunning upset to set up a tournament decider against American John Isner.
Lu defeated the world number three and top seed 6-4, 7-6 (7/4), shattering the Spaniard's dream of winning a record-breaking fifth Auckland title and denting his confidence ahead of next week's Australian Open Grand Slam.
Lu's opponent in the final Isner almost fell victim to an upset himself, coming back from the brink to beat unseeded Spaniard Roberto Bautista Agut 3-6, 7-6 (7/2), 6-4.
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.
"It's incredible," the Taiwanese world number 62 said after the win. "From the beginning of the match I just told myself to win one point, win one game and luckily I won two sets.
"I tried to play my best tennis and fortunately I did it. He's very fast, I had to play aggressive and not give him time."
Aside from a mid-match wobble in the second set, when he served up a string of double faults, Lu looked worthy of the victory against a player who has dominated the Auckland tournament in recent years.
He will hope to take the same form into the final against Isner, whom he has met only once before, when the American demolished him 6-1, 6-2 in Atlanta in 2011.
Isner, who won in Auckland in 2010 and is seeded third this year, looked far from convincing against Bautista Agut.
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 6-3 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.
Isner was down 5-4 and two points away from defeat before he finally rallied and broke back in what proved to be the turning point of the match.
The world number 14 took the subsequent tie-break 7-2 and closed out the deciding set 6-4.
"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.
Isner has played three tough three-setters on his way to the Auckland final but said fatigue would not be a factor against Lu.
"I always look a lot more tired than I actually am on the court," he said. "I'm not playing possum, I'm not doing it on purpose."