Young Frenchman Ugo Humbert has produced one of the performances of the tournament to upset fourth seed John Isner 7-6 6-4 to advance to the ASB Classic final.
The 21-year-old dealt with Isner's powerful serve by matching it with his brute force to send the two-time Classic champion packing.
Humbert won a point of the American's serve in the first set tie break and then broke early in the second set on his way to reaching the final.
He will take on fellow countryman Benoit Paire in the final, after he beat Polish player Hubert Hurkacz 6-4, 6-7, 6-2.
Earlier, in doubles, Kiwi Marcus Daniell and his Austrian partner Philipp Oswald have beaten fourth seeds American Austin Krajicek and Croatian Franko Skugor 6-2, 7-6 to advance to the doubles final.
They will take on Japan's Ben McLachlan and Great Britain's Luke Bambridge who took out Belgium duo Joran Vliegen and Sander Gille.
